ABCC9

This protein forms ATP-sensitive potassium channels in cardiac, skeletal, and smooth muscle by serving as the regulatory subunit that enables channel activation, while partnering with other proteins that form the channel pore. Mutations cause a spectrum of conditions including Cantu syndrome (hypertrichotic osteochondrodysplasia with intellectual disability), dilated cardiomyopathy, and familial atrial fibrillation, with inheritance patterns that can be either autosomal dominant or autosomal recessive. The gene is highly constrained against loss-of-function variants, indicating that complete loss of protein function is likely incompatible with normal development.