The specific aim of this proposal is to collect clinically obtained serial abdominal imaging from the Tuberous Sclerosis Natural History Consortium Centers and analyze the volume and adiposity of the individual angiomyolipomata. The growth rate is hypothesized to have an inverse relationship to adiposity. The prognostic value of identifying lesions with aggressive growth characteristics is very large, and intervention can be instituted early in order to reduce the renal damage.