Parents

One copy of a COL4A3 or COL4A4 mutation results in Autosomal dominant (AD) Alport syndrome. Most people with a single variant have blood in the urine, but some also develop protein in the urine and progressive kidney failure. Hearing loss and ocular abnormalities do not occur with a single pathogenic variant in AD Alport syndrome. The glomerular basement membrane is thinned. AD Alport syndrome affects about one in 100 people

Two copies of a COL4A3 or COL4A4 gene (on opposite chromosomes) result in AR Alport syndrome with haematuria, proteinuria, kidney failure, hearing loss and ocular abnormalities (lenticonus; central and peripheral fleck retinopathy). The glomerular basement membrane is lamellated. This disease is much rarer than AD Alport syndrome.