homocysteinemia
MIM.603174
hyperhomocysteinemia
Various genetic anomalies cause of elevated concentrations of homocysteine (homocystine) in plasma (or serum).
Homocysteinemia is seen in:
homocystinuria (MIM.236200), a disorder most commonly due to cystathione beta-synthase deficiency
vitamin B12 metabolic defect (MIM.277400, MIM.277410) selective intestinal malabsorption of vitamin B12 (MIM.261100)
N(5,10)-methylenetetrahydrofolate reductase deficiency (MIM.236250)
methylcobalamin deficiency cbl G type (MIM.250940)
transcobalamin II deficiency (MIM.275350)
vitamin B12-responsive homocystinuria cbl G type (MIM.250940).
Etiology
methionine synthase deficiency by mutations of gene MTR (1p43)
- Mutations in the MTR gene result in the methylcobalamin deficiency G (cblG) disorder, which is characterized by homocystinuria, hyperhomocysteinemia, and hypomethioninemia.