NKX2-5 and heart disorder: Direct sequencing of NKX2-5 and HAND1 revealed a total of three heterozygous nonsynonymous sequence alterations, two in NKX2-5 and one in HAND1. Both NKX2-5 sequence alterations identified in patients of different cardiac disease phenotypes affected the alanine residue at position 119 and were passed on from an unaffected parent.