MTHFR and acute lymphoblastic leukemia: When the analysis was carried out in different age subgroups, the MTHFR 677 T variant was associated with a decreased susceptibility to pediatric ALL (n = 25, allele contrast: ORRE = 0.90, 95%CI: 0.82-0.997; recessive model: ORFE = 0.85, 95% CI: 0.74-0.96; additive model: ORFE =0.82, 95% CI: 0.71-0.94; Figure 2A), whereas it did not show reduced risk for ALL in adults (n = 6).