An individual (PM) trisomic for the 7.7 Mb region from PSMG1 to PRMT2 had a VSD, whereas the shortest partial trisomy (individual BA) that gave rise to AVSD extended 10.0Mb from HLCS to PRMT2 (Figure 6b). This evidence concerns the gene HLCS and familial atrioventricular septal defect.