MTHFR and acute lymphoblastic leukemia: As for gender, boys with CT or TT genotypes for MTHFR C677T were less likely to develop childhood ALL than those with the homozygous CC genotype (P for trend = 0.0113, OR = 0.54 and 0.32, CI = 0.33–0.89 and 0.11–0.94 for CT and TT, respectively), but this was not the case for the girls (Table 3).