Causes of HHcy include genetic mutations and enzyme deficiencies in 5, 10-methylenetetrahydrofolate reductase (MTHFR) methionine synthase (MS), and cystathionine β-synthase (CβS).
Prevalence of myocardial infarction is related to hyperhomocysteinemia but not influenced by C677T methylenetetrahydrofolate reductase and A2756Gmethionine synthase polymorphisms in diabetic and non-diabetic subjects.
Mutations in methylenetetrahydrofolate reductase (C667T), cystathionine beta-synthase (T833C), and methionine synthase (A2756G) genes cause hyperhomocysteinemia, an independent risk factor for atherothrombosis.
We report here on a case of occlusive stroke at young age and hyperhomocysteinemia with homozygous VN (677C to T) variant in the MTHFR gene as well as homozygous D/D (2756G to A) variant in the MS gene.
We discuss the possibility that a mild deficiency of methionine synthase activity could be associated with mild hyperhomocysteinemia, a risk factor for cardiovascular disease and possibly neural tube defects.