A Human Hereditary Cardiomyopathy Shares a Genetic Substrate With Bicuspid Aortic Valve.

Background: The complex genetics underlying human cardiac disease is evidenced by its heterogenous manifestation, multigenic basis, and sporadic occurrence. These features have hampered disease modeling and mechanistic understanding. Here, we show that 2 structural cardiac diseases, left ventricular noncompaction (LVNC) and bicuspid aortic valve, can be caused by a set of inherited heterozygous gene mutations affecting the NOTCH ligand regulator MIB1 (MINDBOMB1) and cosegregating genes.

Metastable Atrial State Underlies the Primary Genetic Substrate for MYL4 Mutation-Associated Atrial Fibrillation.

Background: Atrial fibrillation (AF) is the most common clinical arrhythmia and is associated with heart failure, stroke, and increased mortality. The myocardial substrate for AF is poorly understood because of limited access to primary human tissue and mechanistic questions around existing in vitro or in vivo models.

Methods: Using an knock-in reporter line, we developed a protocol to generate and highly purify human pluripotent stem cell-derived cardiomyocytes displaying physiological and molecular characteristics of atrial cells.