COL4A5

Alport syndrome

Many variants (also called mutations) in the COL4A5 gene can cause Alport syndrome, a condition characterized by kidney disease, hearing loss, and eye abnormalities. Most of these variants change single protein building blocks (amino acids) in a region where the alpha5(IV) collagen chain combines with other collagen IV chains. Other variants in the COL4A5 gene severely decrease or prevent the production of alpha5(IV) chains. 

These changes in the structure or amount of alpha5(IV) chains severely impair the formation of alpha345(IV) collagen networks in the basement membranes of the kidney, inner ear, and eye. In the kidney, other types of collagen build up in the basement membranes, eventually scarring the kidneys and leading to kidney failure. Variants in this gene can also lead to hearing loss and changes in the lens of the eye and the light-sensitive tissue at the back of the eye (retina).