Table 1. Genotypes of MTHFR.

Genotypes of MTHFR			Prevalence	Activity
677	1298	Name of combined genotype	%	%
CC	AA	Original genotype	16	100
CC	AC	1298C heterozygote	23	60
CC	CC	1298C homozygote	9	52
CT	AA	677T heterozygote	21	51
CT	AC	Compound heterozygote	20	36
TT	AA	677T homozygote	11	22

Overview of prevalence (ref 6) and specific enzyme activity in vitro (ref 7) for various genotypes of MTHFR in healthy individuals, based on combinations of the polymorphisms C677T and A1298C.