Genetic disorders and major extracardiac anomalies associated with the hypoplastic left heart syndrome.

All pediatric autopsies of patients with hypoplastic left heart syndrome seen during an 11-year interval were reviewed to determine the frequency of underlying chromosomal and single-gene defects and idiopathic major extracardiac anomalies associated with this common, lethal congenital heart abnormality. Of 83 patients identified, nine had underlying chromosomal abnormalities, four had single-gene defects, ten had one or more major extracardiac anomalies without an identifiable chromosomal or mendelian disorder, and two were infants of insulin-dependent diabetic mothers. Overall, 23 patients (28%) had a genetic disorder and/or major extracardiac anomaly. The substantial prevalence of genetic causes of and major extracardiac anomalies associated with hypoplastic left heart syndrome underscores the need for a detailed genetic evaluation for all patients with hypoplastic left heart syndrome.