Component of the BLOC-1 complex, a complex that is required for normal biogenesis of lysosome-related organelles (LRO), such as platelet dense granules and melanosomes. In concert with the AP-3 complex, the BLOC-1 complex is required to target membrane protein cargos into vesicles assembled at cell bodies for delivery into neurites and nerve terminals. The BLOC-1 complex, in association with SNARE proteins, is also proposed to be involved in neurite extension. Plays a role in intracellular vesic

Cytoplasm

Hermansky-Pudlak syndrome 8

A form of Hermansky-Pudlak syndrome, a genetically heterogeneous autosomal recessive disorder characterized by oculocutaneous albinism, bleeding due to platelet storage pool deficiency, and lysosomal storage defects. This syndrome results from defects of diverse cytoplasmic organelles including melanosomes, platelet dense granules and lysosomes. Ceroid storage in the lungs is associated with pulmonary fibrosis, a common cause of premature death in individuals with HPS.

Acts as a chaperone that facilitates biogenesis and trafficking of functional transporter heteromers to the plasma membrane (By similarity) (PubMed:10588648, PubMed:11318953, PubMed:16609684, PubMed:16825196, PubMed:32494597, PubMed:32817565, PubMed:7686906, PubMed:8486766, PubMed:8663184, PubMed:8663357). Associates with SLC7A9 to form a functional transporter complex that mediates the electrogenic exchange between cationic amino acids and neutral amino acids, with a stoichiometry of 1:1. SLC7A

Cell membraneApical cell membrane

Cystinuria

An autosomal disorder characterized by impaired epithelial cell transport of cystine and dibasic amino acids (lysine, ornithine, and arginine) in the proximal renal tubule and gastrointestinal tract. The impaired renal reabsorption of cystine and its low solubility causes the formation of calculi in the urinary tract, resulting in obstructive uropathy, pyelonephritis, and, rarely, renal failure.

Positively regulates nitric oxide synthesis in umbilical vein endothelial cells (HUVECs). May be involved in dopamine synthesis. May modify pain sensitivity and persistence. Isoform GCH-1 is the functional enzyme, the potential function of the enzymatically inactive isoforms remains unknown

CytoplasmNucleus

Hyperphenylalaninemia, BH4-deficient, B

A disease characterized by malignant hyperphenylalaninemia due to tetrahydrobiopterin deficiency, and defective neurotransmission due to depletion of the neurotransmitters dopamine and serotonin. The principal symptoms include: psychomotor retardation, tonicity disorders, convulsions, drowsiness, irritability, abnormal movements, hyperthermia, hypersalivation, and difficulty swallowing. Some patients may present a phenotype of intermediate severity between severe hyperphenylalaninemia and mild dystonia. In this intermediate phenotype, there is marked motor delay, but no intellectual disability and only minimal, if any, hyperphenylalaninemia.

Transporter that mediates resorption of neutral amino acids across the apical membrane of renal and intestinal epithelial cells (PubMed:15286787, PubMed:15286788, PubMed:18424768, PubMed:18484095, PubMed:19185582, PubMed:26240152). This uptake is sodium-dependent and chloride-independent (PubMed:15286787, PubMed:15286788, PubMed:19185582). Requires CLTRN in kidney or ACE2 in intestine for cell surface expression and amino acid transporter activity (PubMed:18424768, PubMed:19185582)

Cell membraneApical cell membrane

Hartnup disorder

Autosomal recessive abnormality of renal and gastrointestinal neutral amino acid transport noted for its clinical variability. First described in 1956, HND is characterized by increases in the urinary and intestinal excretion of neutral amino acids. Individuals with typical Hartnup aminoaciduria may be asymptomatic, some develop a photosensitive pellagra-like rash, attacks of cerebellar ataxia and other neurological or psychiatric features. Although the definition of HND was originally based on clinical and biochemical abnormalities, its marked clinical heterogeneity has led to it being known as a disorder with a consistent pathognomonic neutral hyperaminoaciduria.

Key enzyme in methionine and folate homeostasis responsible for the reactivation of methionine synthase (MTR/MS) activity by catalyzing the reductive methylation of MTR-bound cob(II)alamin (PubMed:17892308). Cobalamin (vitamin B12) forms a complex with MTR to serve as an intermediary in methyl transfer reactions that cycles between MTR-bound methylcob(III)alamin and MTR bound-cob(I)alamin forms, and occasional oxidative escape of the cob(I)alamin intermediate during the catalytic cycle leads to

Cytoplasm

Homocystinuria-megaloblastic anemia, cblE type

An autosomal recessive inborn error of metabolism resulting from defects in the cobalamin-dependent pathway that converts homocysteine to methionine. It causes delayed psychomotor development, megaloblastic anemia, homocystinuria, and hypomethioninemia. Cells from patients with HMAE fail to incorporate methyltetrahydrofolate into methionine in whole cells, but cell extracts show normal methionine synthase activity in the presence of a reducing agent.

Carboxyltransferase subunit of the 3-methylcrotonyl-CoA carboxylase, an enzyme that catalyzes the conversion of 3-methylcrotonyl-CoA to 3-methylglutaconyl-CoA, a critical step for leucine and isovaleric acid catabolism

Mitochondrion matrix

3-methylcrotonoyl-CoA carboxylase 2 deficiency

An autosomal recessive disorder of leucine catabolism. The phenotype is variable, ranging from neonatal onset with severe neurological involvement to asymptomatic adults. There is a characteristic organic aciduria with massive excretion of 3-hydroxyisovaleric acid and 3-methylcrotonylglycine, usually in combination with a severe secondary carnitine deficiency.

Involved in vision

Cell projection, cilium, photoreceptor outer segmentMembraneEndoplasmic reticulumGolgi apparatus

Retinitis pigmentosa 36

A retinal dystrophy belonging to the group of pigmentary retinopathies. Retinitis pigmentosa is characterized by retinal pigment deposits visible on fundus examination and primary loss of rod photoreceptor cells followed by secondary loss of cone photoreceptors. Patients typically have night vision blindness and loss of midperipheral visual field. As their condition progresses, they lose their far peripheral visual field and eventually central vision as well.

Has no detectable ceramide-kinase activity. Overexpression of CERKL protects cells from apoptosis in oxidative stress conditions

CytoplasmNucleus, nucleolusGolgi apparatus, trans-Golgi networkEndoplasmic reticulum

Retinitis pigmentosa 26

A retinal dystrophy belonging to the group of pigmentary retinopathies. Retinitis pigmentosa is characterized by retinal pigment deposits visible on fundus examination and primary loss of rod photoreceptor cells followed by secondary loss of cone photoreceptors. Patients typically have night vision blindness and loss of midperipheral visual field. As their condition progresses, they lose their far peripheral visual field and eventually central vision as well.

Essential for the regulation of ciliary length and required for the long-term survival of photoreceptors (By similarity). Phosphorylates FZR1 in a cell cycle-dependent manner. Plays a role in the transcriptional coactivation of AR. Could play an important function in spermatogenesis. May play a role in chromosomal stability in prostate cancer cells

NucleusCytoplasm, cytoskeleton, microtubule organizing center, centrosomeCytoplasm, cytoskeleton, spindleMidbodyCell projection, cilium, photoreceptor outer segmentPhotoreceptor inner segment

Retinitis pigmentosa 62

A retinal dystrophy belonging to the group of pigmentary retinopathies. Retinitis pigmentosa is characterized by retinal pigment deposits visible on fundus examination and primary loss of rod photoreceptor cells followed by secondary loss of cone photoreceptors. Patients typically have night vision blindness and loss of midperipheral visual field. As their condition progresses, they lose their far peripheral visual field and eventually central vision as well.

Catalyzes the ATP-dependent unwinding of U4/U6 RNA duplices, an essential step in the assembly of a catalytically active spliceosome (PubMed:35241646). Plays a role in pre-mRNA splicing as a core component of precatalytic, catalytic and postcatalytic spliceosomal complexes (PubMed:28502770, PubMed:28781166, PubMed:29301961, PubMed:29360106, PubMed:29361316, PubMed:30315277, PubMed:30705154, PubMed:30728453). As a component of the minor spliceosome, involved in the splicing of U12-type introns in

Nucleus

Retinitis pigmentosa 33

A retinal dystrophy belonging to the group of pigmentary retinopathies. Retinitis pigmentosa is characterized by retinal pigment deposits visible on fundus examination and primary loss of rod photoreceptor cells followed by secondary loss of cone photoreceptors. Patients typically have night vision blindness and loss of midperipheral visual field. As their condition progresses, they lose their far peripheral visual field and eventually central vision as well.

The BBSome complex is thought to function as a coat complex required for sorting of specific membrane proteins to the primary cilia. The BBSome complex is required for ciliogenesis but is dispensable for centriolar satellite function. This ciliogenic function is mediated in part by the Rab8 GDP/GTP exchange factor, which localizes to the basal body and contacts the BBSome. Rab8(GTP) enters the primary cilium and promotes extension of the ciliary membrane. Firstly the BBSome associates with the c

Cell projection, cilium membraneCytoplasmCytoplasm, cytoskeleton, microtubule organizing center, centrosome, centriolar satellite

Plays a role in rod outer segment (ROS) morphogenesis (By similarity). May play a role with PRPH2 in the maintenance of the structure of ROS curved disks (By similarity). Plays a role in the organization of the ROS and maintenance of ROS disk diameter (By similarity). Involved in the maintenance of the retina outer nuclear layer (By similarity)

Photoreceptor inner segment membranePhotoreceptor outer segment membrane

Retinitis pigmentosa 7

A retinal dystrophy belonging to the group of pigmentary retinopathies. Retinitis pigmentosa is characterized by retinal pigment deposits visible on fundus examination and primary loss of rod photoreceptor cells followed by secondary loss of cone photoreceptors. Patients typically have night vision blindness and loss of midperipheral visual field. As their condition progresses, they lose their far peripheral visual field and eventually central vision as well.

Accepts electrons from ETF and reduces ubiquinone

Mitochondrion inner membrane

Glutaric aciduria 2C

An autosomal recessively inherited disorder of fatty acid, amino acid, and choline metabolism. It is characterized by multiple acyl-CoA dehydrogenase deficiencies resulting in large excretion not only of glutaric acid, but also of lactic, ethylmalonic, butyric, isobutyric, 2-methyl-butyric, and isovaleric acids.

Heterodimeric electron transfer flavoprotein that accepts electrons from several mitochondrial dehydrogenases, including acyl-CoA dehydrogenases, glutaryl-CoA and sarcosine dehydrogenase (PubMed:10356313, PubMed:15159392, PubMed:15975918, PubMed:27499296, PubMed:9334218). It transfers the electrons to the main mitochondrial respiratory chain via ETF-ubiquinone oxidoreductase (ETF dehydrogenase) (PubMed:9334218). Required for normal mitochondrial fatty acid oxidation and normal amino acid metabol

Mitochondrion matrix

Glutaric aciduria 2A

An autosomal recessively inherited disorder of fatty acid, amino acid, and choline metabolism. It is characterized by multiple acyl-CoA dehydrogenase deficiencies resulting in large excretion not only of glutaric acid, but also of lactic, ethylmalonic, butyric, isobutyric, 2-methyl-butyric, and isovaleric acids.

Microtubule-associated protein involved in membrane protein-cytoskeleton interactions. It is thought to anchor the inhibitory glycine receptor (GLYR) to subsynaptic microtubules (By similarity). Acts as a major instructive molecule at inhibitory synapses, where it also clusters GABA type A receptors (PubMed:25025157, PubMed:26613940) Also has a catalytic activity and catalyzes two steps in the biosynthesis of the molybdenum cofactor. In the first step, molybdopterin is adenylated. Subsequently,

Postsynaptic cell membraneCell membraneCytoplasm, cytosolCytoplasm, cytoskeletonCell projection, dendritePostsynaptic density

Molybdenum cofactor deficiency C

A form of molybdenum cofactor deficiency, an autosomal recessive metabolic disorder leading to the pleiotropic loss of molybdoenzyme activities. It is clinically characterized by onset in infancy of poor feeding, intractable seizures, severe psychomotor retardation, and death in early childhood in most patients.

Catalyzes the NADPH-dependent reduction of trans-2-enoyl thioesters in mitochondrial fatty acid synthesis (fatty acid synthesis type II). Fatty acid chain elongation in mitochondria uses acyl carrier protein (ACP) as an acyl group carrier, but the enzyme accepts both ACP and CoA thioesters as substrates in vitro. Displays a preference for medium-chain over short- and long-chain substrates (PubMed:12654921, PubMed:18479707, PubMed:27817865). May provide the octanoyl chain used for lipoic acid bio

MitochondrionCytoplasmNucleus

Dystonia, childhood-onset, with optic atrophy and basal ganglia abnormalities

An autosomal recessive neurologic disorder characterized by childhood-onset dystonia, basal ganglia degeneration and optic atrophy with decreased visual acuity. Dystonia is defined by the presence of sustained involuntary muscle contraction, often leading to abnormal postures. DYTOABG severity is variable, and some patients lose independent ambulation.

Isoform MOCS1A and isoform MOCS1B probably form a complex that catalyzes the conversion of 5'-GTP to cyclic pyranopterin monophosphate (cPMP) (PubMed:11891227, PubMed:23627491, PubMed:29368224, PubMed:31996372). MOCS1A catalyzes the cyclization of GTP to (8S)-3',8-cyclo-7,8-dihydroguanosine 5'-triphosphate and MOCS1B catalyzes the subsequent conversion of (8S)-3',8-cyclo-7,8-dihydroguanosine 5'-triphosphate to cPMP (PubMed:11891227, PubMed:23627491, PubMed:29368224, PubMed:31996372) Has very wea

Mitochondrion matrixCytoplasm, cytosolCytoplasm

Molybdenum cofactor deficiency A

An autosomal recessive metabolic disorder leading to the pleiotropic loss of molybdoenzyme activities. It is clinically characterized by onset in infancy of poor feeding, intractable seizures, severe psychomotor retardation, and death in early childhood in most patients.

Involved in cobalamin metabolism and trafficking (PubMed:18385497, PubMed:23415655, PubMed:24722857, PubMed:26364851). Plays a role in regulating the biosynthesis and the proportion of two coenzymes, methylcob(III)alamin (MeCbl) and 5'-deoxyadenosylcobalamin (AdoCbl) (PubMed:18385497, PubMed:23415655, PubMed:24722857). Promotes oxidation of cob(II)alamin bound to MMACHC (PubMed:26364851). The processing of cobalamin in the cytosol occurs in a multiprotein complex composed of at least MMACHC, MMA

CytoplasmMitochondrion

Methylmalonic aciduria and homocystinuria, cblD type

An autosomal recessive disorder of cobalamin metabolism characterized by decreased levels of the coenzymes adenosylcobalamin (AdoCbl) and methylcobalamin (MeCbl). Clinical features include developmental delay, hyotonia, intellectual disability, seizures, and megaloblastic anemia. Laboratory studies show methylmalonic aciduria and homocystinuria.

Catalyzes the formation of fatty acid-cholesterol esters, which are less soluble in membranes than cholesterol (PubMed:16154994, PubMed:16647063, PubMed:32433613, PubMed:32433614, PubMed:32944968, PubMed:9020103). Plays a role in lipoprotein assembly and dietary cholesterol absorption (PubMed:16154994, PubMed:9020103). Preferentially utilizes oleoyl-CoA ((9Z)-octadecenoyl-CoA) as a substrate: shows a higher activity towards an acyl-CoA substrate with a double bond at the delta-9 position (9Z) th

Endoplasmic reticulum membrane

Processive actin-based motor that can move in large steps approximating the 36-nm pseudo-repeat of the actin filament. Can hydrolyze ATP in the presence of actin, which is essential for its function as a motor protein (PubMed:10448864). Involved in melanosome transport. Also mediates the transport of vesicles to the plasma membrane (By similarity). May also be required for some polarization process involved in dendrite formation (By similarity)

Griscelli syndrome 1

Rare autosomal recessive disorder that results in pigmentary dilution of the skin and hair, the presence of large clumps of pigment in hair shafts, silvery-gray hair and accumulation of melanosomes in melanocytes. GS1 patients show developmental delay, hypotonia and intellectual disability, without apparent immune abnormalities.

Lipoyl amidotransferase that catalyzes the transfer of lipoyl moieties from lipoyl-protein H of the glycine cleavage system (lipoyl-GCSH) to E2 subunits of the pyruvate dehydrogenase complex (PDCE2) (PubMed:29987032). Unable to catalyze the transfer of octanoyl from octanoyl-GCSH to PDCE2 (PubMed:29987032). In vitro, it is also able to catalyze the transfer of the lipoyl group from lipoyl-AMP to the specific lysine residue of lipoyl domains of lipoate-dependent enzymes but this reaction may not

Mitochondrion

Lipoyltransferase 1 deficiency

An autosomal recessive disorder due to a defect in lipoic acid metabolism, resulting in severe lactic acidosis and metabolic decompensation. Variable clinical manifestations include delayed psychomotor development, severe hypotonia, dystonia, loss of head control, coma, bradycardia, and pulmonary hypertension.

As a major transporter of conjugated bile salts from plasma into the hepatocyte, it plays a key role in the enterohepatic circulation of bile salts necessary for the solubilization and absorption of dietary fat and fat-soluble vitamins (PubMed:14660639, PubMed:24867799, PubMed:34060352, PubMed:8132774). It is strictly dependent on the extracellular presence of sodium (PubMed:14660639, PubMed:24867799, PubMed:34060352, PubMed:8132774). It exhibits broad substrate specificity and transports variou

Cell membrane

Hypercholanemia, familial, 2

An autosomal recessive inborn error of metabolism characterized by persistently increased plasma levels of conjugated bile salts apparent from infancy, fat malabsorption and impaired absorption of fat-soluble vitamins, including D and K. Most patients are asymptomatic. Some neonates may have transient jaundice or transiently elevated liver enzymes.

Plays a role in tight junctions and adherens junctions (By similarity). Acts as a positive regulator of RANKL-induced osteoclast differentiation, potentially via mediating downstream transcriptional activity (By similarity)

Cell junction, adherens junctionCell membraneCell junction, tight junctionNucleus

Hypercholanemia, familial, 1

A disorder characterized by elevated serum bile acid concentrations, itching, and fat malabsorption.

G-protein coupled receptor for glutamate. Ligand binding causes a conformation change that triggers signaling via guanine nucleotide-binding proteins (G proteins) and modulates the activity of down-stream effectors. Signaling activates a phosphatidylinositol-calcium second messenger system. May participate in the central action of glutamate in the CNS, such as long-term potentiation in the hippocampus and long-term depression in the cerebellum (PubMed:24603153, PubMed:28886343, PubMed:7476890).

Cell membranePostsynaptic cell membraneCell projection, dendrite

Spinocerebellar ataxia, autosomal recessive, 13

A form of spinocerebellar ataxia, a clinically and genetically heterogeneous group of cerebellar disorders. Patients show progressive incoordination of gait and often poor coordination of hands, speech and eye movements, due to degeneration of the cerebellum with variable involvement of the brainstem and spinal cord. SCAR13 is characterized by delayed psychomotor development beginning in infancy. Affected individuals show mild to profound intellectual disability with poor or absent speech as well as gait and stance ataxia and hyperreflexia.

Catalyzes the conversion of homogentisate to maleylacetoacetate

Alkaptonuria

An autosomal recessive error of metabolism characterized by an increase in the level of homogentisic acid. The clinical manifestations are urine that turns dark on standing and alkalinization, black ochronotic pigmentation of cartilage and collagenous tissues, and spine arthritis.

Very long-chain specific acyl-CoA dehydrogenase is one of the acyl-CoA dehydrogenases that catalyze the first step of mitochondrial fatty acid beta-oxidation (FAO), breaking down fatty acids into acetyl-CoA and allowing the production of energy from fats (PubMed:17564966, PubMed:18227065, PubMed:7668252, PubMed:9461620, PubMed:9599005, PubMed:9839948). The first step of FAO consists in the proR-proR stereospecific alpha, beta-dehydrogenation of fatty acyl-CoA thioesters using the electron transf

Mitochondrion inner membrane

Acyl-CoA dehydrogenase very long-chain deficiency

An inborn error of mitochondrial fatty acid beta-oxidation which leads to impaired long-chain fatty acid beta-oxidation. It is clinically heterogeneous, with three major phenotypes: a severe childhood form characterized by early onset, high mortality and high incidence of cardiomyopathy; a milder childhood form with later onset, characterized by hypoketotic hypoglycemia, low mortality and rare cardiomyopathy; an adult form, with isolated skeletal muscle involvement, rhabdomyolysis and myoglobinuria, usually triggered by exercise or fasting.

Cobalamin (vitamin B12) cytosolic chaperone that catalyzes the reductive decyanation of cyanocob(III)alamin (cyanocobalamin, CNCbl) to yield cob(II)alamin and cyanide, using FAD or FMN as cofactors and NADPH as cosubstrate (PubMed:18779575, PubMed:19700356, PubMed:21697092, PubMed:25809485). Cyanocobalamin constitutes the inactive form of vitamin B12 introduced from the diet, and is converted into the active cofactors methylcobalamin (MeCbl) involved in methionine biosynthesis, and 5'-deoxyadeno

Cytoplasm, cytosol

Methylmalonic aciduria and homocystinuria, cblC type

An autosomal recessive disorder of cobalamin metabolism characterized by decreased levels of the coenzymes adenosylcobalamin (AdoCbl) and methylcobalamin (MeCbl). Affected individuals may have developmental, hematologic, neurologic, metabolic, ophthalmologic, and dermatologic clinical findings. Although considered a disease of infancy or childhood, some individuals develop symptoms in adulthood.

Together with PDHA1 forms the heterotetrameric E1 subunit of the pyruvate dehydrogenase (PDH) complex (PubMed:17474719, PubMed:19081061). The PDH complex catalyzes the overall conversion of pyruvate to acetyl-CoA and CO(2), and thereby links cytoplasmic glycolysis and the mitochondrial tricarboxylic acid (TCA) cycle (Probable). It contains multiple copies of three enzymatic components: pyruvate dehydrogenase (E1), dihydrolipoamide acetyltransferase (E2) and dihydrolipoamide dehydrogenase (E3) (P

Mitochondrion matrix

Pyruvate dehydrogenase E1-beta deficiency

An enzymatic defect causing primary lactic acidosis in children. It is associated with a broad clinical spectrum ranging from fatal lactic acidosis in the newborn to chronic neurologic dysfunction with structural abnormalities in the central nervous system without systemic acidosis.

Magnesium-independent polyisoprenoid diphosphatase that catalyzes the sequential dephosphorylation of presqualene, farnesyl, geranyl and geranylgeranyl diphosphates (PubMed:16464866, PubMed:19220020, PubMed:20110354). Functions in the innate immune response through the dephosphorylation of presqualene diphosphate which acts as a potent inhibitor of the signaling pathways contributing to polymorphonuclear neutrophils activation (PubMed:16464866, PubMed:23568778). May regulate the biosynthesis of

Endoplasmic reticulum membraneNucleus envelopeNucleus inner membrane

The pyruvate dehydrogenase (PDH) complex, catalyzes the overall conversion of pyruvate to acetyl-CoA and CO(2), and thereby links cytoplasmic glycolysis and the mitochondrial tricarboxylic acid (TCA) cycle (Probable). It contains multiple copies of three enzymatic components: pyruvate dehydrogenase (E1), dihydrolipoamide acetyltransferase (E2) and dihydrolipoamide dehydrogenase (E3); (Probable). Within this complex, the catalytic function of this enzyme is to accept, and to transfer to coenzyme

Mitochondrion matrix

Sodium-dependent, high-affinity amino acid transporter that mediates the uptake of L-glutamate and also L-aspartate and D-aspartate (PubMed:21123949, PubMed:26690923, PubMed:33658209, PubMed:7521911, PubMed:7914198, PubMed:8857541). Can also transport L-cysteine (PubMed:21123949). Functions as a symporter that transports one amino acid molecule together with two or three Na(+) ions and one proton, in parallel with the counter-transport of one K(+) ion (PubMed:26690923, PubMed:33658209, PubMed:75

Cell membraneApical cell membraneSynapse, synaptosomeEarly endosome membraneLate endosome membraneRecycling endosome membrane

Dicarboxylic aminoaciduria

An autosomal recessive disorder characterized by abnormal excretion of urinary glutamate and aspartate, resulting from the incomplete reabsorption of anionic amino acids from the glomerular filtrate in the kidney. It can be associated with intellectual disability.

Bifunctional enzyme that catalyzes the first two steps in lysine degradation

Mitochondrion

Hyperlysinemia, 1

An autosomal recessive metabolic condition with variable clinical features. Some patients present with non-specific seizures, hypotonia, or mildly delayed psychomotor development, and increased serum lysine and pipecolic acid on laboratory analysis. However, about half of the probands are reported to be asymptomatic, and hyperlysinemia is generally considered to be a benign metabolic variant.

Calcium, potassium:sodium antiporter that transports 1 Ca(2+) and 1 K(+) to the melanosome in exchange for 4 cytoplasmic Na(+) (PubMed:18166528). Involved in pigmentation, possibly by participating in ion transport in melanosomes (PubMed:16357253, PubMed:18166528). Predominant sodium-calcium exchanger in melanocytes (PubMed:16357253, PubMed:18166528)

Golgi apparatus, trans-Golgi network membraneMelanosome

Albinism, oculocutaneous, 6

A disorder characterized by a reduction or complete loss of melanin in the skin, hair and eyes. Patients show reduced or lacking pigmentation often accompanied by eye symptoms such as photophobia, strabismus, moderate to severe visual impairment, and nystagmus.

Mitochondrial electrogenic aspartate/glutamate antiporter that favors efflux of aspartate and entry of glutamate and proton within the mitochondria as part of the malate-aspartate shuttle (PubMed:11566871, PubMed:38937634, PubMed:38945283, PubMed:39419476). Substrate exchange across the membrane occurs consecutively with one substrate being transported first, then dissociating from the substrate binding site before the second substrate binds for transport in the opposite direction (PubMed:389376

Mitochondrion inner membrane

Citrin deficiency, adolescent or adult onset

An autosomal recessive metabolic disorder characterized by elevated serum and urine citrulline levels, ammonia intoxication, and neuropsychiatric symptoms including abnormal behaviors, loss of memory, seizures and coma. Death can result from brain edema.

Catalyzes the reversible interconversion of L-ornithine and 2-oxoglutarate to L-glutamate semialdehyde and L-glutamate

Mitochondrion matrix

Hyperornithinemia with gyrate atrophy of choroid and retina

A disorder clinically characterized by a triad of progressive chorioretinal degeneration, early cataract formation, and type II muscle fiber atrophy. Characteristic chorioretinal atrophy with progressive constriction of the visual fields leads to blindness at the latest during the sixth decade of life. Patients generally have normal intelligence.

Converts proline to delta-1-pyrroline-5-carboxylate

Mitochondrion matrix

Hyperprolinemia 1

An inborn error of proline metabolism resulting in elevated levels of proline in the plasma and urine. The disorder is generally benign and most affected individuals are clinically asymptomatic. Some patients, however, have neurologic manifestations, including epilepsy and intellectual disability. Association with certain forms of schizophrenia have been reported.

Coenzyme A (CoA) transferase that reversibly catalyzes the transfer of a CoA moiety from a dicarboxyl-CoA to a dicarboxylate in a metabolite recycling process. Displays preference for succinyl-CoA and glutarate-CoA as dicarboxyl-CoA donors and glutarate, succinate, adipate/hexanedioate, itaconate and 3-hydroxy-3-methylglutarate as dicarboxylate acceptors (PubMed:23893049, PubMed:34492704, PubMed:38915184). Acts on intermediates or end products of lysine and tryptophan degradation pathway, in par

Mitochondrion

Glutaric aciduria 3

An autosomal recessive metabolic condition characterized by urinary excretion of abnormal quantities of glutaric acid, in the presence of normal 3-hydroxyglutarate, glutarylcarnitine and glutarylglycine urinary levels. Affected individuals show no consistent clinical phenotype and many are asymptomatic.

Catalyzes the cleavage of L-kynurenine (L-Kyn) and L-3-hydroxykynurenine (L-3OHKyn) into anthranilic acid (AA) and 3-hydroxyanthranilic acid (3-OHAA), respectively. Has a preference for the L-3-hydroxy form. Also has cysteine-conjugate-beta-lyase activity

Cytoplasm, cytosol

Hydroxykynureninuria

An inborn error of amino acid metabolism characterized by massive urinary excretion of large amounts of kynurenine, 3-hydroxykynurenine and xanthurenic acid. Affected individuals manifest renal tubular dysfunction, metabolic acidosis, psychomotor retardation, non-progressive encephalopathy, and muscular hypertonia.

2-oxoadipate dehydrogenase (E1a) component of the 2-oxoadipate dehydrogenase complex (OADHC) (PubMed:29191460, PubMed:29752936, PubMed:32303640, PubMed:32633484, PubMed:32695416). Participates in the first step, rate limiting for the overall conversion of 2-oxoadipate (alpha-ketoadipate) to glutaryl-CoA and CO(2) catalyzed by the whole OADHC (PubMed:29191460, PubMed:32695416). Catalyzes the irreversible decarboxylation of 2-oxoadipate via the thiamine diphosphate (ThDP) cofactor and subsequent t

Mitochondrion

Charcot-Marie-Tooth disease, axonal, type 2Q

An axonal form of Charcot-Marie-Tooth disease, a disorder of the peripheral nervous system, characterized by progressive weakness and atrophy, initially of the peroneal muscles and later of the distal muscles of the arms. Charcot-Marie-Tooth disease is classified in two main groups on the basis of electrophysiologic properties and histopathology: primary peripheral demyelinating neuropathies (designated CMT1 when they are dominantly inherited) and primary peripheral axonal neuropathies (CMT2). Neuropathies of the CMT2 group are characterized by signs of axonal degeneration in the absence of obvious myelin alterations, normal or slightly reduced nerve conduction velocities, and progressive distal muscle weakness and atrophy.

Regulator subunit of pancreatic ATP-sensitive potassium channel (KATP), playing a major role in the regulation of insulin release. In pancreatic cells, it forms KATP channels with KCNJ11; KCNJ11 forms the channel pore while ABCC8 is required for activation and regulation

Cell membrane

Leucine-induced hypoglycemia

Rare cause of hypoglycemia and is described as a condition in which symptomatic hypoglycemia is provoked by high protein feedings. Hypoglycemia is also elicited by administration of oral or intravenous infusions of a single amino acid, leucine.

Catalyzes the conversion of gamma-aminobutyrate and L-beta-aminoisobutyrate to succinate semialdehyde and methylmalonate semialdehyde, respectively (PubMed:10407778, PubMed:15528998). Can also convert delta-aminovalerate and beta-alanine (By similarity)

Mitochondrion matrix

GABA-transaminase deficiency

An enzymatic deficiency resulting in psychomotor retardation, hypotonia, hyperreflexia, lethargy, refractory seizures, and EEG abnormalities. GABATD inheritance is autosomal recessive.

Biotin-attachment subunit of the 3-methylcrotonyl-CoA carboxylase, an enzyme that catalyzes the conversion of 3-methylcrotonyl-CoA to 3-methylglutaconyl-CoA, a critical step for leucine and isovaleric acid catabolism

Mitochondrion matrix

3-methylcrotonoyl-CoA carboxylase 1 deficiency

An autosomal recessive disorder of leucine catabolism. The phenotype is variable, ranging from neonatal onset with severe neurological involvement to asymptomatic adults. There is a characteristic organic aciduria with massive excretion of 3-hydroxyisovaleric acid and 3-methylcrotonylglycine, usually in combination with a severe secondary carnitine deficiency.

Catalytic subunit of the essential mitochondrial processing protease (MPP), which cleaves the mitochondrial sequence off newly imported precursors proteins (Probable) (PubMed:29576218). Preferentially, cleaves after an arginine at position P2 (By similarity). Required for PINK1 turnover by coupling PINK1 mitochondrial import and cleavage, which results in subsequent PINK1 proteolysis (PubMed:22354088)

Mitochondrion matrix

Multiple mitochondrial dysfunctions syndrome 6

An autosomal recessive, neurodegenerative disorder characterized by basal ganglia lesions, cerebellar atrophy, and neurologic regression in the first year of life. Common features include truncal hypotonia, lack of independent ambulation, poor speech, intellectual disability, and motor abnormalities, such as ataxia, dystonia, and spasticity.

Involved in the maturation of mitochondrial 4Fe-4S proteins functioning late in the iron-sulfur cluster assembly pathway. May be involved in the binding of an intermediate of Fe/S cluster assembly

Mitochondrion

Multiple mitochondrial dysfunctions syndrome 4

A severe disorder of systemic energy metabolism, resulting in weakness, respiratory failure, lack of neurologic development, lactic acidosis, hyperglycinemia and early death.

Mediates the uptake of pyruvate into mitochondria to maintain the balance between glycolysis and oxidative phosphorylation (PubMed:22628558, PubMed:26253029, PubMed:27317664, PubMed:40044865, PubMed:40101766). Plays an essential role in cellular metabolism (PubMed:40044865, PubMed:40101766)

Mitochondrion inner membrane

Mitochondrial pyruvate carrier deficiency

An autosomal recessive metabolic disorder characterized by severely delayed psychomotor development, mild dysmorphic features, hepatomegaly, marked metabolic acidosis, hyperlactacidemia with normal lactate/pyruvate, and encephalopathy. Some patients have epilepsy and peripheral neuropathy.

Methylmalonyl-CoA epimerase involved in propionyl-CoA metabolism

Mitochondrion

Methylmalonyl-CoA epimerase deficiency

Autosomal recessive inborn error of amino acid metabolism, involving valine, threonine, isoleucine and methionine. This organic aciduria may present in the neonatal period with life-threatening metabolic acidosis, hyperammonemia, feeding difficulties, pancytopenia and coma.

Membrane

Lysosomal membrane chaperone required to export cobalamin (vitamin B12) from the lysosome to the cytosol, allowing its conversion to cofactors (PubMed:19136951). Targets ABCD4 transporter from the endoplasmic reticulum to the lysosome (PubMed:27456980). Then forms a complex with lysosomal ABCD4 and cytoplasmic MMACHC to transport cobalamin across the lysosomal membrane (PubMed:25535791). Acts as an adapter protein which plays an important role in mediating and regulating the internalization of t

Endoplasmic reticulum membraneLysosome membraneCell membraneCytoplasmic vesicle, clathrin-coated vesicle

Methylmalonic aciduria and homocystinuria, cblF type

An autosomal recessive disorder of cobalamin metabolism characterized by decreased levels of the coenzymes adenosylcobalamin (AdoCbl) and methylcobalamin (MeCbl). It is due to accumulation of free cobalamin in lysosomes, thus hindering its conversion to cofactors. Clinical features include developmental delay, stomatitis, glossitis, seizures and methylmalonic aciduria responsive to vitamin B12.

Transcriptional coregulator (By similarity). Serves as a scaffold protein, bridging interactions between transcription factors, including THAP11 and ZNF143, and transcriptional coregulators (PubMed:26416877). Involved in control of the cell cycle (PubMed:10629049, PubMed:10779346, PubMed:15190068, PubMed:16624878, PubMed:23629655). Also antagonizes transactivation by ZBTB17 and GABP2; represses ZBTB17 activation of the p15(INK4b) promoter and inhibits its ability to recruit p300 (PubMed:10675337

CytoplasmNucleus

Methylmalonic aciduria and homocystinuria, cblX type

An X-linked recessive metabolic disorder characterized by severely delayed psychomotor development apparent in infancy, failure to thrive, impaired intellectual development, and intractable epilepsy. Additional features may include microcephaly and choreoathetosis.

Malonate and methylmalonate semialdehyde dehydrogenase involved in the catabolism of valine, thymine, and compounds catabolized by way of beta-alanine, including uracil and cytidine

Mitochondrion

Methylmalonate semialdehyde dehydrogenase deficiency

A metabolic disorder characterized by elevated beta-alanine, 3-hydroxypropionic acid, and both isomers of 3-amino and 3-hydroxyisobutyric acids in urine organic acids.

Non-receptor tyrosine kinase involved in B-lymphocyte development, differentiation and signaling (By similarity). B-cell receptor (BCR) signaling requires a tight regulation of several protein tyrosine kinases and phosphatases, and associated coreceptors (By similarity). Binding of antigen to the B-cell antigen receptor (BCR) triggers signaling that ultimately leads to B-cell activation (By similarity). Signaling through BLK plays an important role in transmitting signals through surface immunog

Cell membrane

Maturity-onset diabetes of the young 11

A form of diabetes that is characterized by an autosomal dominant mode of inheritance, onset in childhood or early adulthood (usually before 25 years of age), a primary defect in insulin secretion and frequent insulin-independence at the beginning of the disease.

Insulin decreases blood glucose concentration. It increases cell permeability to monosaccharides, amino acids and fatty acids. It accelerates glycolysis, the pentose phosphate cycle, and glycogen synthesis in liver

Secreted

Hyperproinsulinemia

An autosomal dominant condition characterized by elevated levels of serum proinsulin-like material.

Mitochondrial ornithine-citrulline antiporter (Probable) (PubMed:12807890, PubMed:22262851). Catalyzes the exchange between cytosolic ornithine and mitochondrial citrulline plus an H(+), the proton compensates the positive charge of ornithine thus leading to an electroneutral transport. Plays a crucial role in the urea cycle, by connecting the cytosolic and the intramitochondrial reactions of the urea cycle (Probable) (PubMed:12807890, PubMed:22262851). Lysine and arginine are also transported b

Mitochondrion inner membraneMitochondrion membrane

Hyperornithinemia-hyperammonemia-homocitrullinuria syndrome

An autosomal recessive disorder of the urea cycle characterized by onset in early life. The acute phase of the disease is characterized by vomiting, ataxia, lethargy, confusion, and coma. Chronic clinical manifestations include hypotonia, developmental delay, progressive encephalopathy with mental regression, and spastic paraparesis with pyramidal signs.

Component of the BLOC-1 complex, a complex that is required for normal biogenesis of lysosome-related organelles (LRO), such as platelet dense granules and melanosomes. In concert with the AP-3 complex, the BLOC-1 complex is required to target membrane protein cargos into vesicles assembled at cell bodies for delivery into neurites and nerve terminals. The BLOC-1 complex, in association with SNARE proteins, is also proposed to be involved in neurite extension. Associates with the BLOC-2 complex

CytoplasmCytoplasmic vesicle membraneEndosome membraneMelanosome membranePostsynaptic densityEndoplasmic reticulumNucleusCytoplasmic vesicle, secretory vesicle, synaptic vesicle membranePostsynaptic cell membrane

Hermansky-Pudlak syndrome 7

A form of Hermansky-Pudlak syndrome, a genetically heterogeneous autosomal recessive disorder characterized by oculocutaneous albinism, bleeding due to platelet storage pool deficiency, and lysosomal storage defects. This syndrome results from defects of diverse cytoplasmic organelles including melanosomes, platelet dense granules and lysosomes. Ceroid storage in the lungs is associated with pulmonary fibrosis, a common cause of premature death in individuals with HPS.

Sodium- and chloride-dependent glycine transporter (PubMed:8183239). Essential for regulating glycine concentrations at inhibitory glycinergic synapses Sodium- and chloride-dependent glycine transporter Sodium- and chloride-dependent glycine transporter

Cell membrane

Glycine encephalopathy with normal serum glycine

An autosomal recessive, severe metabolic disorder characterized by arthrogryposis multiplex congenita, joint hyperlaxity, lack of neonatal respiratory effort, axial hypotonia, hypertonia with pronounced clonus, and delayed psychomotor development. Some patients may have dysmorphic facial features and/or brain imaging abnormalities. Laboratory studies show increased CSF glycine and normal or only mildly increased serum glycine. Most patients die in infancy.

The glycine cleavage system catalyzes the degradation of glycine

Mitochondrion

Glycine encephalopathy 2

A form of glycine encephalopathy, a metabolic disorder characterized by a high concentration of glycine in the body fluids. Affected individuals typically have severe neurological symptoms, including seizure, lethargy, and muscular hypotonia soon after birth. Most of them die within the neonatal period. Atypical cases have later disease onset and less severely affected psychomotor development.

Interconverts simultaneously and stereospecifically pyruvate and lactate with concomitant interconversion of NADH and NAD(+)

CytoplasmMitochondrion inner membrane

Lactate dehydrogenase B deficiency

A condition with no deleterious effects on health. LDHBD is of interest to laboratory medicine mainly because it can cause misdiagnosis in those disorders in which elevation of serum LDH is expected.

Pyruvate kinase that catalyzes the conversion of phosphoenolpyruvate to pyruvate with the synthesis of ATP, and which plays a key role in glycolysis

Pyruvate kinase hyperactivity

Autosomal dominant phenotype characterized by increase of red blood cell ATP.

Member of the ionotropic glutamate receptor family, which plays a crucial role in synaptic organization and signal transduction in the central nervous system. Although it shares structural features with ionotropic glutamate receptors, does not bind glutamate as a primary ligand (PubMed:34936451). Promotes synaptogenesis and mediates the D-Serine-dependent long term depression signals and AMPA receptor endocytosis of cerebellar parallel fiber-Purkinje cell (PF-PC) synapses through the NRX1B-CBLN1

Postsynaptic cell membrane

Spinocerebellar ataxia, autosomal recessive, 18

A form of spinocerebellar ataxia, a clinically and genetically heterogeneous group of cerebellar disorders. Patients show progressive incoordination of gait and often poor coordination of hands, speech and eye movements, due to degeneration of the cerebellum with variable involvement of the brainstem and spinal cord. SCAR18 features include progressive cerebellar atrophy, delayed psychomotor development, severely impaired gait, ocular movement abnormalities, and intellectual disability.

Bifunctional enzyme that converts glutamate to glutamate 5-semialdehyde, an intermediate in the biosynthesis of proline, ornithine and arginine

MitochondrionMitochondrion matrix

Cutis laxa, autosomal recessive, 3A

A syndrome characterized by facial dysmorphism with a progeroid appearance, large and late-closing fontanel, cutis laxa, joint hyperlaxity, athetoid movements and hyperreflexia, pre- and postnatal growth retardation, intellectual deficit, developmental delay, and ophthalmologic abnormalities.

May be involved in modulating the expression of photoreceptor specific genes. Binds to the Ret-1 and Bat-1 element within the rhodopsin promoter

Nucleus

Macular degeneration, age-related, 6

A form of age-related macular degeneration, a multifactorial eye disease and the most common cause of irreversible vision loss in the developed world. In most patients, the disease is manifest as ophthalmoscopically visible yellowish accumulations of protein and lipid that lie beneath the retinal pigment epithelium and within an elastin-containing structure known as Bruch membrane.

Component of the IFT complex A (IFT-A), a complex required for retrograde ciliary transport and entry into cilia of G protein-coupled receptors (GPCRs) (PubMed:20889716, PubMed:22503633). Plays a pivotal role in proper development and function of ciliated cells through its role in ciliogenesis and/or cilium maintenance (PubMed:22503633). Required for the development and maintenance of the outer segments of rod and cone photoreceptor cells. Plays a role in maintenance and the delivery of opsin to

Cytoplasm, cytoskeleton, cilium basal bodyCytoplasm, cytoskeleton, microtubule organizing center, centrosomeCell projection, cilium

Short-rib thoracic dysplasia 9 with or without polydactyly

A form of short-rib thoracic dysplasia, a group of autosomal recessive ciliopathies that are characterized by a constricted thoracic cage, short ribs, shortened tubular bones, and a 'trident' appearance of the acetabular roof. Polydactyly is variably present. Non-skeletal involvement can include cleft lip/palate as well as anomalies of major organs such as the brain, eye, heart, kidneys, liver, pancreas, intestines, and genitalia. Some forms of the disease are lethal in the neonatal period due to respiratory insufficiency secondary to a severely restricted thoracic cage, whereas others are compatible with life. Disease spectrum encompasses Ellis-van Creveld syndrome, asphyxiating thoracic dystrophy (Jeune syndrome), Mainzer-Saldino syndrome, and short rib-polydactyly syndrome. SRTD9 is characterized by phalangeal cone-shaped epiphyses, chronic renal disease, nearly constant retinal dystrophy, and mild radiographic abnormality of the proximal femur. Occasional features include short stature, cerebellar ataxia, and hepatic fibrosis.

Plays an essential role for normal photoreceptor cell maintenance and vision

Cell projection, cilium, photoreceptor outer segmentPhotoreceptor inner segment

Retinitis pigmentosa 54

A retinal dystrophy belonging to the group of pigmentary retinopathies. Retinitis pigmentosa is characterized by retinal pigment deposits visible on fundus examination and primary loss of rod photoreceptor cells followed by secondary loss of cone photoreceptors. Patients typically have night vision blindness and loss of midperipheral visual field. As their condition progresses, they lose their far peripheral visual field and eventually central vision as well.

Involved in pre-mRNA splicing as component of the spliceosome (PubMed:11867543, PubMed:20118938, PubMed:28781166). Required for the assembly of the U4/U5/U6 tri-snRNP complex, one of the building blocks of the spliceosome (PubMed:11867543)

NucleusNucleus speckleNucleus, Cajal body

Retinitis pigmentosa 11

A retinal dystrophy belonging to the group of pigmentary retinopathies. Retinitis pigmentosa is characterized by retinal pigment deposits visible on fundus examination and primary loss of rod photoreceptor cells followed by secondary loss of cone photoreceptors. Patients typically have night vision blindness and loss of midperipheral visual field. As their condition progresses, they lose their far peripheral visual field and eventually central vision as well.

Serves as the first electron transfer protein in all the mitochondrial P450 systems including cholesterol side chain cleavage in all steroidogenic tissues, steroid 11-beta hydroxylation in the adrenal cortex, 25-OH-vitamin D3-24 hydroxylation in the kidney, and sterol C-27 hydroxylation in the liver (By similarity). Also acts as a ferredoxin--NADP(+) reductase essential for coenzyme Q biosynthesis: together with FDX2, transfers the electrons required for the hydroxylation reaction performed by C

MitochondrionMitochondrion inner membrane

Auditory neuropathy and optic atrophy

An autosomal recessive disease characterized by hearing loss, visual impairment and optic atrophy, with onset in the first or second decades of life. Optic atrophy is caused by degeneration of nerve fibers which arise in the retina and converge to form the optic disk, optic nerve, optic chiasm and optic tracts.

Catalyzes the reversible isomerization of methylmalonyl-CoA (MMCoA) (generated from branched-chain amino acid metabolism and degradation of dietary odd chain fatty acids and cholesterol) to succinyl-CoA (3-carboxypropionyl-CoA), a key intermediate of the tricarboxylic acid cycle

Mitochondrion matrixMitochondrionCytoplasm

Methylmalonic aciduria due to methylmalonyl-CoA mutase deficiency

An often fatal disorder of organic acid metabolism. Common clinical features include lethargy, vomiting, failure to thrive, hypotonia, neurological deficit and early death. Two forms of the disease are distinguished by the presence (mut-) or absence (mut0) of residual enzyme activity. Mut0 patients have more severe neurological manifestations of the disease than do MUT- patients. MAMM is unresponsive to vitamin B12 therapy.

Thiol-specific peroxidase that catalyzes the reduction of hydrogen peroxide and organic hydroperoxides to water and alcohols, respectively. Plays a role in cell protection against oxidative stress by detoxifying peroxides and as sensor of hydrogen peroxide-mediated signaling events. Might participate in the signaling cascades of growth factors and tumor necrosis factor-alpha by regulating the intracellular concentrations of H(2)O(2) (PubMed:9497357). Reduces an intramolecular disulfide bond in G

CytoplasmMelanosome

Catalyzes the hydrolysis of a wide range of substrates including cholesteryl esters, phospholipids, lysophospholipids, di- and tri-acylglycerols, and fatty acid esters of hydroxy fatty acids (FAHFAs) (PubMed:10220579, PubMed:27509211, PubMed:27650499, PubMed:8471055). Preferentially hydrolyzes FAHFAs with the ester bond further away from the carboxylate. Unsaturated FAHFAs are hydrolyzed more quickly than saturated FAHFAs (By similarity). Has an essential role in the complete digestion of dietar

Secreted

Maturity-onset diabetes of the young 8 with exocrine dysfunction

An autosomal dominant form of diabetes characterized by a primary defect in insulin secretion, exocrine pancreatic dysfunction, altered pancreatic morphology, recurrent abdominal pain, and fecal elastase deficiency. Disease onset is at less than 25 years of age.

Transcription factor (PubMed:10207080, PubMed:9748269). Activates the epsilon- and gamma-globin gene promoters and, to a much lower degree, the beta-globin gene and represses promoters containing SP1-like binding inhibiting cell growth (PubMed:10207080, PubMed:16131492, PubMed:9748269). Represses transcription of SMAD7 which enhances TGF-beta signaling (By similarity). Induces apoptosis (By similarity)

Nucleus

Maturity-onset diabetes of the young 7

A form of diabetes that is characterized by an autosomal dominant mode of inheritance, onset in childhood or early adulthood (usually before 25 years of age), a primary defect in insulin secretion and frequent insulin-independence at the beginning of the disease.

Plays an important role in the differentiation and development of pancreatic islet beta cells. Transcriptional repressor that binds to a common element in the glucagon, insulin and somatostatin promoters. Competes with PAX6 for this same promoter binding site. Isoform 2 appears to be a dominant negative form antagonizing PAX4 transcriptional activity

Nucleus

Type 2 diabetes mellitus

A multifactorial disorder of glucose homeostasis caused by a lack of sensitivity to insulin. Affected individuals usually have an obese body habitus and manifestations of a metabolic syndrome characterized by diabetes, insulin resistance, hypertension and hypertriglyceridemia. The disease results in long-term complications that affect the eyes, kidneys, nerves, and blood vessels.

Transcriptional regulator which controls the expression of hepatic genes during the transition of endodermal cells to hepatic progenitor cells, facilitating the recruitment of RNA pol II to the promoters of target genes (PubMed:30597922). Activates the transcription of CYP2C38 (By similarity). Represses the CLOCK-BMAL1 transcriptional activity and is essential for circadian rhythm maintenance and period regulation in the liver and colon cells (PubMed:30530698)

Nucleus

Maturity-onset diabetes of the young 1

A form of diabetes that is characterized by an autosomal dominant mode of inheritance, onset in childhood or early adulthood (usually before 25 years of age), a primary defect in insulin secretion and frequent insulin-independence at the beginning of the disease.

Catalyzes the oxidation of sulfite to sulfate, the terminal reaction in the oxidative degradation of sulfur-containing amino acids

Mitochondrion intermembrane space

Sulfite oxidase deficiency, isolated

A life-threatening, autosomal recessive neurometabolic disorder characterized by severe neurological impairment. Classic ISOD manifests in the first few hours to days of life and is characterized by intractable seizures, feeding difficulties, rapidly progressive encephalopathy, microcephaly, and profound intellectual disability. Children usually die during the first few months of life. Mild ISOD manifests in infancy or early childhood and is characterized by ectopia lentis that is variably present, developmental delay and regression, movement disorder characterized by dystonia and choreoathetosis, ataxia, and rarely acute hemiplegia due to metabolic stroke.

Catalyzes the conversion of L-tyrosine to L-dihydroxyphenylalanine (L-Dopa), the rate-limiting step in the biosynthesis of catecholamines, dopamine, noradrenaline, and adrenaline. Uses tetrahydrobiopterin and molecular oxygen to convert tyrosine to L-Dopa (PubMed:15287903, PubMed:1680128, PubMed:17391063, PubMed:24753243, PubMed:34922205, PubMed:8528210, Ref.18). In addition to tyrosine, is able to catalyze the hydroxylation of phenylalanine and tryptophan with lower specificity (By similarity).

Cytoplasm, perinuclear regionNucleusCell projection, axonCytoplasmCytoplasmic vesicle, secretory vesicle, synaptic vesicle

Segawa syndrome autosomal recessive

A form of DOPA-responsive dystonia presenting in infancy or early childhood. Dystonia is defined by the presence of sustained involuntary muscle contractions, often leading to abnormal postures. Some cases present with parkinsonian symptoms in infancy. Unlike all other forms of dystonia, it is an eminently treatable condition, due to a favorable response to L-DOPA.

Acts as a guanine nucleotide exchange factor (GEF) for RhoA GTPases. Its activation induces formation of actin stress fibers. Also acts as a GEF for RAC1, inducing production of reactive oxygen species (ROS). Does not act as a GEF for CDC42. The G protein beta-gamma (Gbetagamma) subunits of heterotrimeric G proteins act as activators, explaining the integrated effects of LPA and other G-protein coupled receptor agonists on actin stress fiber formation, cell shape change and ROS production. Requi

CytoplasmCytoplasm, cytoskeletonCell membraneApical cell membrane

Retinitis pigmentosa 78

A form of retinitis pigmentosa, a retinal dystrophy belonging to the group of pigmentary retinopathies. Retinitis pigmentosa is characterized by retinal pigment deposits visible on fundus examination and primary loss of rod photoreceptor cells followed by secondary loss of cone photoreceptors. Patients typically have night vision blindness and loss of midperipheral visual field. As their condition progresses, they lose their far peripheral visual field and eventually central vision as well. RP78 inheritance is autosomal recessive.

Centrosomal protein required for establishing a robust mitotic centrosome architecture that can endure the forces that converge on the centrosomes during spindle formation. Required for stabilizing the expanded pericentriolar material around the centriole

Cytoplasm, cytoskeleton, microtubule organizing center, centrosomeCytoplasm, cytoskeleton, cilium basal body

Retinitis pigmentosa 69

A retinal dystrophy belonging to the group of pigmentary retinopathies. Retinitis pigmentosa is characterized by retinal pigment deposits visible on fundus examination and primary loss of rod photoreceptor cells followed by secondary loss of cone photoreceptors. Patients typically have night vision blindness and loss of midperipheral visual field. As their condition progresses, they lose their far peripheral visual field and eventually central vision as well.

Imports 4-aminobutanoate (GABA) into lysosomes. May act as a GABA sensor that regulates mTORC2-dependent INS signaling and gluconeogenesis. The transport mechanism and substrate selectivity remain to be elucidated

Lysosome membrane

Retinitis pigmentosa 68

A retinal dystrophy belonging to the group of pigmentary retinopathies. Retinitis pigmentosa is characterized by retinal pigment deposits visible on fundus examination and primary loss of rod photoreceptor cells followed by secondary loss of cone photoreceptors. Patients typically have night vision blindness and loss of midperipheral visual field. As their condition progresses, they lose their far peripheral visual field and eventually central vision as well.

Involved in membrane protein trafficking at the base of the ciliary organelle. Mediates recruitment onto plasma membrane of the BBSome complex which would constitute a coat complex required for sorting of specific membrane proteins to the primary cilia (PubMed:20603001). Together with BBS1, is necessary for correct trafficking of PKD1 to primary cilia (By similarity). Together with the BBSome complex and LTZL1, controls SMO ciliary trafficking and contributes to the sonic hedgehog (SHH) pathway

Cell projection, cilium membraneCytoplasm, cytoskeleton, cilium axonemeCytoplasm, cytoskeleton, cilium basal body

Bardet-Biedl syndrome 3

A syndrome characterized by usually severe pigmentary retinopathy, early-onset obesity, polydactyly, hypogenitalism, renal malformation and intellectual disability. Secondary features include diabetes mellitus, hypertension and congenital heart disease. Bardet-Biedl syndrome inheritance is autosomal recessive, but three mutated alleles (two at one locus, and a third at a second locus) may be required for clinical manifestation of some forms of the disease.

Photoreceptor required for image-forming vision at low light intensity (PubMed:7846071, PubMed:8107847). Required for photoreceptor cell viability after birth (PubMed:12566452, PubMed:2215617). Light-induced isomerization of the chromophore 11-cis-retinal to all-trans-retinal triggers a conformational change that activates signaling via G-proteins (PubMed:26200343, PubMed:28524165, PubMed:28753425, PubMed:8107847). Subsequent receptor phosphorylation mediates displacement of the bound G-protein

MembraneCell projection, cilium, photoreceptor outer segment

Retinitis pigmentosa 4

A retinal dystrophy belonging to the group of pigmentary retinopathies. Retinitis pigmentosa is characterized by retinal pigment deposits visible on fundus examination and primary loss of rod photoreceptor cells followed by secondary loss of cone photoreceptors. Patients typically have night vision blindness and loss of midperipheral visual field. As their condition progresses, they lose their far peripheral visual field and eventually central vision as well.

Involved in hearing and vision as member of the USH2 complex. In the inner ear, required for the maintenance of the hair bundle ankle formation, which connects growing stereocilia in developing cochlear hair cells. In retina photoreceptors, the USH2 complex is required for the maintenance of periciliary membrane complex that seems to play a role in regulating intracellular protein transport

Cell projection, stereocilium membraneSecreted

Usher syndrome 2A

USH is a genetically heterogeneous condition characterized by the association of retinitis pigmentosa with sensorineural deafness. Age at onset and differences in auditory and vestibular function distinguish Usher syndrome type 1 (USH1), Usher syndrome type 2 (USH2) and Usher syndrome type 3 (USH3). USH2 is characterized by congenital mild hearing impairment with normal vestibular responses.

Functions as an E3 ubiquitin-protein ligase and as an E3 SUMO1-protein ligase. Probable tumor suppressor involved in cell growth, cell proliferation and apoptosis that regulates p53/TP53 stability through ubiquitin-dependent degradation. May regulate chromatin modification through sumoylation of several chromatin modification-associated proteins. May be involved in DNA damage-induced cell death through IKBKE sumoylation

NucleusNucleus, PML body

Retinitis pigmentosa 31

A retinal dystrophy belonging to the group of pigmentary retinopathies. Retinitis pigmentosa is characterized by retinal pigment deposits visible on fundus examination and primary loss of rod photoreceptor cells followed by secondary loss of cone photoreceptors. Patients typically have night vision blindness and loss of midperipheral visual field. As their condition progresses, they lose their far peripheral visual field and eventually central vision as well.

This is one of the 2 subunits of the biotin-dependent propionyl-CoA carboxylase (PCC), a mitochondrial enzyme involved in the catabolism of odd chain fatty acids, branched-chain amino acids isoleucine, threonine, methionine, and valine and other metabolites (PubMed:6765947, PubMed:8434582). Propionyl-CoA carboxylase catalyzes the carboxylation of propionyl-CoA/propanoyl-CoA to D-methylmalonyl-CoA/(S)-methylmalonyl-CoA (PubMed:10101253, PubMed:6765947, PubMed:8434582). Within the holoenzyme, the

Mitochondrion matrix

Propionic acidemia type I

Life-threatening disease characterized by episodic vomiting, lethargy and ketosis, neutropenia, periodic thrombocytopenia, hypogammaglobulinemia, developmental retardation, and intolerance to protein.

Catalyzes the reversible oxidation of 3-phospho-D-glycerate to 3-phosphonooxypyruvate, the first step of the phosphorylated L-serine biosynthesis pathway. Also catalyzes the reversible oxidation of 2-hydroxyglutarate to 2-oxoglutarate and the reversible oxidation of (S)-malate to oxaloacetate

Phosphoglycerate dehydrogenase deficiency

An autosomal recessive inborn error of L-serine biosynthesis, clinically characterized by congenital microcephaly, psychomotor retardation, and seizures.

Inward rectifier potassium channel that forms the pore of ATP-sensitive potassium channels (KATP), regulating potassium permeability as a function of cytoplasmic ATP and ADP concentrations in many different cells (PubMed:29286281, PubMed:34815345). Inward rectifier potassium channels are characterized by a greater tendency to allow potassium to flow into the cell rather than out of it. Their voltage dependence is regulated by the concentration of extracellular potassium; as external potassium is

Membrane

Hyperinsulinemic hypoglycemia, familial, 2

A form of hyperinsulinemic hypoglycemia, a clinically and genetically heterogeneous disorder characterized by inappropriate insulin secretion from the pancreatic beta-cells in the presence of low blood glucose levels. HHF2 is a common cause of persistent hypoglycemia in infancy. Unless early and aggressive intervention is undertaken, brain damage from recurrent episodes of hypoglycemia may occur. HHF2 inheritance can be autosomal dominant or autosomal recessive.

Catalyzes the conversion of malonyl-CoA to acetyl-CoA. In the fatty acid biosynthesis MCD selectively removes malonyl-CoA and thus assures that methyl-malonyl-CoA is the only chain elongating substrate for fatty acid synthase and that fatty acids with multiple methyl side chains are produced. In peroxisomes it may be involved in degrading intraperoxisomal malonyl-CoA, which is generated by the peroxisomal beta-oxidation of odd chain-length dicarboxylic fatty acids. Plays a role in the metabolic

CytoplasmMitochondrion matrixPeroxisomePeroxisome matrix

Malonyl-CoA decarboxylase deficiency

Autosomal recessive disease characterized by abdominal pain, chronic constipation, episodic vomiting, metabolic acidosis and malonic aciduria.