MTHFD1 and coronary artery disorder: MTHFD1 R653Q (rs2236225 G → A) and MTHFD1 R134K (rs1950902 G → A) as the two most well-studied polymorphisms [21], previous efforts involved in the associations of children’s genetic polymorphisms with CHD risk had yielded conflicting results [14, 22–27], and there were few studies on the associations of maternal genetic polymorphisms with CHD risk [14, 16].