hypermethioninemia

Genetics

• autosomal recessive > autosomal dominant
• associated with defects in AHCY, MAT1A, GNMT

Clinical manifestations

• fetid breath & dimethylsulfide
• clinical consequences are poorly understood
• in some individuals, hypermethioninemia is apparently benign
• in others, association of neurological problems with null mutations has been observed

Laboratory

• elevated levels of methionine in serum/plasma
• dimethylsulfide excretion (expired air)
• adenosylhomocysteine hydrolase in erythrocytes low to absent

More general terms

• amino acid inborn error of metabolism

More specific terms

• glycine N-methyltransferase deficiency (GNMT deficiency)

Database

• OMIM: https://mirror.omim.org/entry/180960