Familial atrial septal defect and atrioventricular conduction disturbance associated with a point mutation in the cardiac homeobox gene CSX/NKX2-5 ina Japanese patient

Atrial septal defect (ASD) is the most common fern? of congenital cardiac d efect in humans. Recently, point mutations in the cardiac homeobox gene CSX /NKX2-5 have been reported to cause the autosomal dominant form of familial ASD. Notably, all the affected patients exhibit atrioventricular conductio n disturbance and some of them died suddenly. The first case of familial AS D with a mutation of the CSX/NKX2-5 gene in a Japanese patient is reported here. Identification of CSX/NKX2-5 mutations in ASD patients would be very important because the existence of such mutations may predict sudden cardia c death.