Distribution of Type IV Collagen in the Cochlea in Alport Syndrome

Abstract
Alport syndrome, an inherited progressive renal disease with sensorineural hearing loss (SNHL) and ocular lesions, is caused by mutations in the genes (COL4) that code for the α3, α4, or α5 chains of type IV collagen.1-3 The disease is genetically heterogeneous with X-linked, autosomal recessive and autosomal dominant forms. Most cases (approximately 85%) of Alport syndrome are X-linked and are due to mutations in the COL4A5 gene located on Xq22 that codes for the α5 chain of type IV collagen. More than 300 mutations of the COL4A5 gene producing X-linked Alport syndrome have been reported.