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Amino acid and nitrogen metabolism defects

39 articles

Methylmalonyl-CoA mutase

Methylmalonyl-CoA mutase (MCM, MMUT), mitochondrial B12-dependent enzyme EC 5.4.99.2 converting methylmalonyl-CoA to succinyl-CoA via adenosylcobalamin radical mechanism; deficiency causes methylmalonic acidemia; gene therapies now in trials.

Molybdenum cofactor deficiency

Molybdenum cofactor deficiency (MoCD), types A/B/C from MOCS1, MOCS2, MOCS3, or GPHN mutations, is an autosomal recessive metabolic disease causing sulfite oxidase loss, neonatal seizures, and encephalopathy; fosdenopterin treats type A.

N-Acetylglutamate synthase

N-Acetylglutamate synthase (NAGS, EC 2.3.1.1) is a mitochondrial liver enzyme making N-acetylglutamate, the activator of CPSI in the urea cycle; arginine activates it in mammals but inhibits microbial NAGS, and its inherited deficiency causes hyperammonemia treated with carglumic acid.

Ornithine transcarbamylase

Ornithine transcarbamylase (OTC, EC 2.1.3.3), also ornithine carbamoyltransferase, is a mitochondrial matrix enzyme of the urea cycle converting carbamoyl phosphate and ornithine to citrulline; X-linked OTC deficiency causes the most common urea cycle disorder.

Ornithine transcarbamylase deficiency

Ornithine transcarbamylase deficiency (OTC deficiency) is an inherited X-linked metabolic disorder that impairs the urea cycle, letting ammonia reach neurotoxic levels; it is the most common urea cycle disorder.

Ornithine translocase deficiency

Ornithine translocase deficiency, also called HHH syndrome or ORNT1 deficiency, is a rare autosomal recessive urea cycle disorder caused by SLC25A15 mutations, causing hyperornithinemia, hyperammonemia, and homocitrullinuria.

Propionic acidemia

Propionic acidemia (PA), also called propionyl-CoA carboxylase deficiency, is a rare autosomal recessive metabolic disorder from PCCA or PCCB mutations, causing neonatal metabolic acidosis, hyperammonemia, cardiomyopathy, and neurological damage.

Short/branched-chain acyl-CoA dehydrogenase deficiency

Short/branched-chain acyl-CoA dehydrogenase deficiency, also called 2-methylbutyryl-CoA dehydrogenase deficiency or 2-methylbutyrylglycinuria, is a rare autosomal recessive ACADSB disorder of isoleucine breakdown, usually asymptomatic and detected by newborn screening.

Transcobalamin II deficiency

Transcobalamin II deficiency is a rare autosomal recessive TCN2 disorder in which vitamin B12 cannot enter cells, causing megaloblastic anemia, immunodeficiency, and pancytopenia in early infancy.