Hereditary nephritis (also known as Alport syndrome), also a heritable disorder of type IV collagen, is a rare cause of end-stage kidney disease with a prevalence of 0.4% among adult U.S. patients. Most cases are X- linked (80%) and are associated with sensorineural hearing loss and lenticonus (conical deformation of the lens), with proteinuria, hypertension, and kidney failure developing over time. The remaining cases are autosomal recessive (15%) or autosomal dominant (5%) and may also be associated with hearing loss. Female carriers variably develop kidney disease depending on activity of the X chromosome in somatic renal cells.