|| common in clinvar
|?|| (A;A) (A;G) (G;G) ||28|
Methionine synthase, coded by the MTR gene, has a B12 attached to it. The Methionine synthase takes a methyl group from methyl folate and attaches it to its B12, then it attaches it to a molecule of homocysteine, turning it into methionine, which in turn becomes SAMe. After 1000-2000 times doing this, the B12 gets turned into a useless form, and MTRR turns the B12 back into the useful form so that the molecule of MTR can keep working. The MTRR mutations make this enzyme less active, suggesting a need for more B12.
[PMID 19493349] 118 SNPs of folate-related genes and risks of spina bifida and conotruncal heart defects.
[PMID 20445798] Chromosome 5p Region SNPs Are Associated with Risk of NSCLC among Women.