It has been reported that SNPs in genes such as NK2 homeobox 5(NKX2-5), GATA binding protein 4(GATA4), T-box transcription factor 20(TBX-20), myosin heavy chain 6(MYH6), methylenetetrahydrofolate reductase(MTHFR), and connexin 43(Cx43) are significantly related to the risk of ASD [18–20]. The gene discussed is MTHFR; the disease is atrial septal defect.