image

Close-up of a gross specimen showing the surface of a human kidney in a case of autosomal dominant polycystic kidney disease (ADPKD). The surface is full of large cysts. ADPKD is caused by mutations in PKD genes that produce a specific abnormal protein that has an adverse effect on tubule development. (KEYSTONE/SCIENCE PHOTO LIBRARY/JOSE CALVO / SCIENCE PHOTO LIBRARY)