It has still not been elucidated whether the degree of hyperhomocysteinemia is significantly higher in homozygous than in heterozygous carriers, however, it has been shown that hyperhomocysteinemia in the presence of this genetic mutation manifests only in the case of low folate levels, making folate deficiency a likely explanation for the expression of the MTHFR thermo liable genotype (14-16). Here, MTHFR is linked to hyperhomocysteinemia.