Type of disease: Rare conditions
Alport syndrome is a genetic condition that affects a person’s kidneys, eyes, and hearing. Almost everyone with Alport syndrome will have blood in the urine (hematuria) and most will have protein in the urine (proteinuria). As time goes on, Alport syndrome continues to damage the kidneys and may lead to kidney failure in some people. Other features of Alport syndrome include hearing loss, which typically starts in late childhood or early teenage years, and eye abnormalities, which includes an abnormal shape to the lens (anterior lenticonus) and abnormal coloration to the back of the eye (retina). Eye changes in Alport syndrome usually do not affect vision.
Alport syndrome is caused by changes (mutations) in a few genes, including COL4A3, COL4A4, and COL4A5. All three of these genes provide instructions for the body to make type IV collagen, which is a protein needed for proper kidney blood vessel function, inner ear formation, and eye shape. When a person has mutations in one of these genes, type IV collagen is not made correctly, which leads to the symptoms of Alport syndrome. Alport syndrome is caused by mutations in the COL4A5 gene in 80% of cases and by mutations in the COL4A3 and COL4A4 genes in 15% of cases. Alport syndrome caused by COL4A5 gene mutations is inherited in an X-linked recessive manner and, when it is caused by mutations in COL4A3 and COL4A4, it is inherited in an autosomal recessive manner.
A diagnosis of Alport syndrome is considered in a person with kidney issues and hearing loss. Genetic testing is used to confirm the diagnosis. Treatment usually involves medications to help protect kidney function and, in severe cases, a kidney transplant may be needed. Hearing aids can help with hearing loss. If your child has been diagnosed with Alport syndrome, talk with their doctor to discuss current treatment options. Support groups can provide additional information.