GWAS-driven Pathway Analyses and Functional Validation Suggest GLIS1 as a Susceptibility Gene for Mitral Valve Prolapse

Nonsyndromic Mitral valve prolapse (MVP) is a common degenerative valvular heart disease with severe health consequences, including arrhythmia, heart failure and sudden death. MVP is characterized by excess extracellular matrix secretion and cellular disorganization which leads to bulky valves that are unable to co-apt properly during ventricular systole. However, the triggering mechanisms of this process are mostly unknown. Using pathway enrichment tools applied to GWAS we show that genes at risk loci are involved in biological functions relevant to cell adhesion and migration during cardiac development and in response to shear stress. Through genetic, in silico and in vivo experiments we demonstrates the presence of several genes involved in gene regulation, including GLIS1, a transcription factor that regulates Hedgehog signaling. Our findings define genetic, molecular and cellular mechanisms underlying non-syndromic MVP and implicate disrupted endothelial to mesenchymal transition and cell migration as a potential common cause to this disease.