MTHFR and isolated spina bifida: Two single nucleotide polymorphisms (SNPs) of the MTHFR gene, MTHFR 677C>T and 1298A>C, have been well studied and are known to be associated with various diseases such as cancer, coronary heart disease, neural tube defect, ischemic stroke, and osteoporotic fractures [13,14,15,16,17,18].