In this study, the combined effects of methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism and folate and vitamin B12 deficiency on serum total Hcy (tHcy) levels were evaluated in a healthy Chinese population in Yunnan Province, China.
In this study, our aim was to investigate the association of methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism on the vitamin B12 therapy response in 95 patients with vitamin B12 deficiency and 92 healthy control subjects using vitamin B12, plasma total homocysteine (tHcy), and folate as the main measure of outcome.
One of the plausible reasons for susceptibility of individuals with MTHFRC677T in the studied population to various disorders is the high frequency of hyperhomocysteinemia and vitamin B12 deficiency in the 'healthy population'.
Hyperhomocysteinaemia (HCA) either due to mutation of MTHFR gene or deficiency of vitamin B 12 and folic acid, has been reported as a risk factor for coronary artery disease (CAD).
High frequency of vitamin B12 deficiency in asymptomatic individuals homozygous to MTHFRC677T mutation is associated with endothelial dysfunction and homocysteinemia.
Hyperhomocysteinemia, a risk factor for thrombosis, recurrent miscarriages, and osteoporosis, might derive from acquired folate and vitamin B 12 deficiencies and from a C677T mutation in methylene-tetrahydrofolate reductase (MTHFR) gene.
We report the lack of megaloblastic anaemia in a patient with severe methionine synthase deficiency who is also homozygous for C677T in MTHFR, hypothesize that the MTHFR polymorphism protects the patient against anaemia and speculate that homozygosity for MTHFRC677T could cause the dissociation between haematological and neurological disease seen in some patients with vitamin B12 deficiency.