TSC1 and angiomyolipoma: The condition is characterized by varied contributions of adipocytes, smooth muscle cells, and endothelial cells, and genetic analysis has revealed that the second genetic hit is present in all three cell lineages in angiomyolipoma which indicates that the three elements arise from a common precursor cell that has undergone inactivation of both alleles, either TSC1 or TSC24,6,10.