MTRR and spina bifida: However, until now, only a few genes have been reported to represent risk factors for spina bifida, including 5,10-methylenetetrahydrofolate reductase (MTHFR; 1p36.3) [170], methionine synthase reductase (MTRR; 5p15.3-p15.2) [171], platelet-derived growth factor receptor alpha (PDGFRA; 4q11-q13) [172] endothelial nitric oxide synthase 3 (NOS3; 7q36) [173] protein-L-isoaspartate (D-aspartate) O-methyltransferase (PCMT1; 6q24-q25) [174] and cofilin 1 (non-muscle) (CFL1; 11q13) [175].