On the other hand, MTHFR 677 CC wildtype was a risk genotype for developing leukemia in children from Europe and America (Europe: RR = 1.11, 95% CI [1.02, 1.22], p = .0207; America: RR = 1.09, 95% CI [1.02, 1.20], p = .0451). The gene discussed is MTHFR; the disease is leukemia.