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.