MTHFR and acute lymphoblastic leukemia: Carriership of single nucleotide polymorphisms (SNPs) in, for example, the MTHFR, MTRR, and VDR genes has been associated with low BMD at ALL diagnosis and during ALL treatment45,46, and SNPs near glutamate receptor genes, in the ACP1 gene, and in the VDR Fok I start site have been associated with the development of osteonecrosis28,43,47.