Calcium-dependent cell-adhesion protein. Mediates functions in neuroprogenitor cell proliferation and differentiation. In the heart, has a critical role for proper morphogenesis of the mitral valve, acting in the regulation of cell migration involved in valve formation (PubMed:26258302). Heterophilic interaction with FAT4; this interaction affects their respective protein levels. In the embryonic cortex, FAT4 and DCHS1 accumulated at the cell-cell boundaries located apical to the adherens junction. Expressed in the epicardium and atrioventricular sulcus (at protein level). Expressed in all layers of the developing brain, with expression being most prominent at the ventricular margin. Expressed throughout cardiac development in the endothelial cells and interstitial cells of the developing valves (at protein level). Expression is observed in the endocardium and mesenchyme of the superior and inferior cushions at day 11.5 dpc. At days 13.5 dpc and 15.5 dpc, expression is observed in the forming anterior and posterior mitral leaflets (PubMed:26258302). Deficient mice exhibit postnatal lethality, growth retardation, small lungs, abnormal cochlea morphology, abnormal kidney morphology, cardiovascular abnormalities and skeletal abnormalities. DCHS1 and FAT4 single mutants and DCHS1/FAT4 double mutants have similar phenotypes. Heterozygous mice lacking one DCHS1 allele exhibit mitral valve prolapse with posterior leaflet elongation, leaflet thickening, and myxomatous degeneration with increased proteoglycan accumulation in both mitral leaflets (PubMed:26258302).