Risk of Congenital Heart Defects in Relatives of Patients With Atrioventricular Canal

• OBJECTIVE. —To investigate the overall occurrence of congenital heart disease in 103 pedigrees with a proband affected with atrioventricular canal. DESIGN. —Family study of patient series. SETTING. —Department of Pediatric Cardiology, Bambino Gesu' Hospital, Rome, Italy. PARTICIPANTS. —One hundred three consecutive patients with atrioventricular canal and normal karyotype and their first- and second-degree relatives. INTERVENTIONS. —None. MEASUREMENTS/MAIN RESULTS. —In 12 pedigrees (11.7%), one or more relatives had concordant or discordant congenital heart disease. Congenital heart disease occurred in four (1.9%) of the 206 parents of probands, in four (3.6%) of the 111 siblings, and in five (0.8%) of the 644 uncles or aunts. None of the grandparents had congenital heart disease. Atrioventricular canal affected several family members in five pedigrees. CONCLUSIONS. —Familial aggregation of atrioventricular canal in several pedigrees requires careful collection of family histories, accurate cardiologic evaluation of the first-and second-degree relatives of the probands, and fetal echocardiography in all pregnant women in at-risk families.(AJDC. 1993;147:1295-1297)