| An inherited disease characterized by glomerular nephropathy with hematuria, progressing to end-stage renal disease, associated with sensorineural deafness. It involves a structural defect of type IV collagen, which is a normal component of the glomerular basal membrane. Ocular abnormalities are present a third of cases. Sensorineural deafness is linked to cochlear involvement. Mutations in the COL4A5 gene localized on chromosome Xq22 and coding for the alpha 5 chain of type IV collagen are responsible for the most frequent form of the disease. Mutations in COL4A3 and COL4A4 genes, which map to chromosome 2, are responsible for the less frequent autosomal recessive form. A few rare cases of autosomal dominant forms have been reported. |
