描述
Glycine N-methyltransferase deficiency (GNMT deficiency) is caused by mutation in the GNMT gene (606628). Glycine N-methyltransferase catalyzes the synthesis of N-methylglycine (sarcosine) from glycine using S-adenosylmethionine (AdoMet) as the methyl donor. GNMT acts as an enzyme to regulate the ratio of S-adenosylmethionine to S-adenosylhomocysteine (AdoHcy) and participates in the detoxification pathway in liver cells. A defect in this enzyme causes accumulation of methionine in the plasma and transaminases in the serum. Symptoms include hepatomegaly.