Nephrin plays a role in the development or function of the kidney glomerular filtration barrier. Nephrin regulates glomerular vascular permeability, and anchors the podocyte slit diaphragm to the actin cytoskeleton. Nephrin interacts with CD2AP (via C-terminal domain). Nephrin plays a role in skeletal muscle formation through regulation of myoblast fusion. Defects in NPHS1 are the cause of nephrotic syndrome type 1 (NPHS1), also known as Finnish congenital nephrosis (CNF). NPHS1 is a renal disease characterized clinically by proteinuria, hypoalbuminemia, hyperlipidemia, and edema. Kidney biopsies show non-specific histologic changes such as focal segmental glomerulosclerosis and diffuse mesangial proliferation.