Familial Incidence of Cardiovascular Malformations in Hypoplastic Left Heart Syndrome.

Obstructive left-sided congenital heart lesions exhibit familial clustering, and familial echocardiographic screening for bicuspid aortic valve has become standard practice. Hypoplastic left heart syndrome (HLHS) is a severe left-sided obstructive lesion; however, familial screening is not universally recommended. The purpose of this study was to define the incidence of cardiovascular malformations (CVMs) in first-degree relatives of HLHS probands. First-degree relatives were screened for CVM by transthoracic echocardiography. Screening was completed in 152 family members (97 parents and 55 siblings) of 52 probands. Of these, 17 of 152 (11%) had CVM. Anomalies detected included: bicuspid aortic valve in 5 (3%), isolated dilated ascending aorta in 4 (3%), coarctation of the aorta in 1, partial anomalous pulmonary venous connection in 1, anomalous, intramural coronary artery in 1, bicuspid pulmonary valve in 1, and other anomalies in 4. Most were previously undiagnosed (11 of 17, 65%). Fourteen of 52 families (27%) had ≥1 relative with CVM. Overall, 7 of 55 siblings (13%), 5 of 46 fathers (11%) and 5 of 51 mothers (10%) had CVM. Although the incidence of CVM in first-degree relatives of HLHS probands was lower in this cohort than previously reported, it remained substantial, with at least one additional member having CVM in 27% of families. The frequent occurrence of undiagnosed CVM highlights the importance of routine familial screening in HLHS. In fact, even if screening was done in childhood, it may be appropriate to screen again in the third or fourth decade to exclude isolated enlargement of the ascending aorta.