Endothelin-Converting Enzyme-1 (ECE-1) is a single-pass type I I transmembrane (TM) protein with a short cytoplasmic tail and a large ectodomain. ECE-1 is a zinc protease of the neprilysin (NEP) family, which also includes ECE-2, PEX, XCE, DINE, and Kell, and several NEP-like proteins. It is widely expressed and has several alternatively spliced forms that differ in their TM domain or cytoplasmic tail. All isoforms of ECE-1 are expressed in umbilical vein endothelial cells, polynuclear neutrophils, fibroblasts, atrium cardiomyocytes and ventricles. Endothelin-converting enzyme-1 is involved in the proteolytic processing of Endothelin-1 (EDN1), Endothelin-2 (EDN2), and Endothelin-3 (EDN3) to biologically active peptides. Defects in ECE1 are a cause of Hirschsprung disease, cardiac defects and autonomic dysfunction (HSCRCDAD). It is a form of Hirschsprung disease with skip-lesions defects, craniofacial abnormalities and other dysmorphic features, and autonomic dysfunction.