MTHFR and acute lymphoblastic leukemia: In our pediatric ALL patients, the frequencies of the MTHFR 677 CC, CT, and TT variants were 48.8%, 41.8%, and 9.3%, respectively, and the frequencies of the MTHFR 1298 AA, AC, and CC variants were 51.2%, 37.2%, and 11.6%, respectively.