many patients rapidly developing severe encephalopathy. One consequence of reduced methionine synthase activity that is measurable by routine clinical blood tests is megaloblastic anemia. Genetics Several cblG-associated polymorphisms in the MTR gene have been identified. 2756D→G (Asp919Gly) 3804C→T (Pro1137Leu) Δ2926A-2928T (ΔIle881) See also Methyltransferase Arakawa's syndrome II Betaine—homocysteine S-methyltransferase References Further reading External links GeneReviews/NCBI/NIH/UW entry on Disorders of Intracellular Cobalamin Metabolism ENZYME: EC 2.1.1.13 EC 2.1.1 Human proteins Zinc enzymes