A study published in 2011 reported a significant association between an increased likelihood of hematologic toxicity (anemia) and the MTHFD1 rs2236225 AA/AG genotypes in 50 children from multiethnic ancestry (Caucasian, Afro-Caribbean, Indian) with OS, treated with MTX (p = 0.044) [46]. The gene discussed is MTHFD1; the disease is anemia (phenotype).