MTHFR and acute lymphoblastic leukemia: Additionally, children and adolescents with ALL and the C allele sequences (AC and CC) of the 1298A>C polymorphism of the MTHFR gene did not present a statistically significant difference in their frequency compared to that in a healthy population (OR: 1.01; CI: 0.95–1.08; p = 0.69) (Figure 3).