Inherited<unk>  that is not associated with other metabolic disorders can be caused by shortages in the enzymes that break down methionine. These enzymes are produced from the MAT1A, GNMT and AHCY genes. The reactions involved in metabolizing methionine help supply some of the amino acids needed for protein production. These reactions are also involved in transferring methyl groups, consisting of a carbon atom and three hydrogen atoms, from one molecule to another (transmethylation), which is important in many cellular processes. * The MAT1A gene provides instructions for producing the enzyme methionine adenosyltransferase. This enzyme converts methionine into a compound called S-adenosylmethionine. * The GNMT gene provides instructions for making the enzyme glycine N-methyltransferase. This enzyme starts the next step in the process, converting S-adenosylmethionine to a compound called S-adenosyl homocysteine. * The AHCY gene provides instructions for producing the enzyme S-adenosylhomocysteine hydrolase. This enzyme converts the S-adenosyl homocysteine into the compound homocysteine. Homocysteine may be converted back to methionine or into another amino acid, cysteine. A deficiency of any of these enzymes results in a buildup of methionine in the body, and may cause signs and symptoms related to<unk> .
Hypermethioninemia
Hypervalinemia
Hyperammonemia
Hyperphenylalaninemia
Hypouricemia
Hyperaemia
Isovaleric acidemia
Hyperlysinemia