A total of 12 genetic variants were detected of which seven (58%) were located within the tail domain of MYH3. The non-synonymous variant c.5254G>A (p. Ala1752Thr) was identified in two female ASD patients having ASD secundum with defect size of 0.5 cm and 0.8 cm respectively but was absent in the 73 unrelated controls. The gene discussed is MYH3; the disease is atrial septal defect.