Loss-of-function variants in ciliary genes confer high risk for tetralogy of Fallot.

Abstract

Tetralogy of Fallot (TOF), the most common severe cyanotic congenital heart disease, has unclear genetic causes. Through next-generation sequencing in 131 patients with nonsyndromic TOF, we identified an increased burden of rare deleterious variants in ciliary genes and cilium pathway and observed a multigenic inheritance pattern, with an odds ratio (OR) of 1.672 [95% confidence interval (CI), 1.120 to 2.547; <i>P</i> = 0.0104] for more than two deleterious variants and a cumulative OR of 3.158 (95% CI, 1.381 to 6.371; <i>P</i> = 0.0038) for six variants. Functional validation in single- and double-heterozygous mouse models carrying these variants recapitulated TOF-like phenotypes and impaired normal cilia structure and function, particularly disrupting Hedgehog signaling in cardiomyocytes, and down-regulating key transcription factors <i>Gata4</i> and <i>Nkx2-5</i>. Together, our study provides compelling evidence linking ciliary gene variants to a heightened risk of TOF in Han Chinese, offering valuable genetic insights into the etiology and pathogenesis of nonsyndromic TOF and supporting a multigenic inheritance model for the disease.