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Alport syndrome

Other Names for this Disease
  • Alport syndrome, X-linked
  • Congenital hereditary hematuria
  • Hemorrhagic familial nephritis
  • Hemorrhagic hereditary nephritis
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What causes Alport syndrome?

Alport syndrome may be caused by mutations in either the COL4A3, COL4A4, or COL4A5 genes. These genes each provide instructions for making one component of a protein called type IV collagen, which plays an important role in the glomeruli of the kidneys. Glomeruli are clusters of specialized blood vessels that remove water and waste products from the blood and create urine. Mutations in the genes mentioned above result in abnormalities of the type IV collagen in glomeruli, which prevents the kidneys from properly filtering the blood. As a result, blood and protein pass into the urine. Over time, the kidneys become scarred and many people with Alport syndrome develop kidney failure.[1]

Type IV collagen is also an important component of the organ of Corti, an inner ear structure that transforms sound waves into nerve impulses for the brain. Alterations in type IV collagen may result in abnormal inner ear function, which can lead to hearing loss. In addition, type IV collagen plays a role in the eye, where it helps maintain the shape of the lens and the normal color of the retina. Mutations found in Alport syndrome may affect the shape of the lenses and the color of the retina.[1]

Last updated: 8/1/2013

  1. Alport syndrome. Genetics Home Reference. April 2009; Accessed 10/24/2011.