HLHS Genetic Study Shows Basis for Heart Failure in Single Ventricle Circulations

Recently, one of our HLHS researchers, Dr. Jeanne Theis, had her study published in Circulation: Cardiovascular Genetics. This exciting paper focuses on heterozygous MYH6 mutations, or mutations of a certain gene.

Nowadays, children born with HLHS are living well into adulthood due to many advances in surgical techniques including the Norwood Procedure, the Glenn Procedure and the Fontan Procedure. During the final procedure, the Fontan, the right ventricle of the heart is surgically structured to act as a systematic pump and reduce the overall workload of the right ventricle. However, in some patients with HLHS, this procedure may lead to an eventual decline in the heart’s performance and may even lead to needing a heart transplant.

Dr. Theis’ study compared whole genome sequencing of families and discovered recessive, heterozygous MYH6 mutations in two patients with HLHS who developed heart failure three to eleven years after the Fontan procedure. Heterozygous MYH6 mutations have been identified in patients with other congenital heart defects and dilated cardiomyopathy. This current study links concern over this minor myosin heavy chain isoform to developmental arrest and latent myopathy of left and right ventricles. In summary, this study has uncovered a genetic basis for heart failure in single ventricle circulations and may make it possible to find new strategies to predict and prevent adverse outcomes in patients with HLHS.

The Todd and Karen Wanek Family Program for Hypoplastic Left Heart Syndrome (HLHS) is a collaborative network of specialists bonded by the vision of delaying or preventing heart failure for individuals affected by congenital heart defects including HLHS. The specialized team is addressing the various aspects of these defects by using research and clinical strategies ranging from basic science to diagnostic imaging to regenerative therapies.