TSC1 is a tumor suppressor gene that encodes a 130 kDa protein called hamartin. TSC1 was first identified as an oncogenic driver of Tuberous Sclerosis, a condition characterized by numerous benign tumors of the skin, brain, heart, and lungs. A mutation in TSC1 is responsible for the uncontrolled growth characteristic of these tumors. This discovery led to a greater understanding of the physiologic role of TSC1 as a negative cell cycle regulator. The distinct but related gene TSC2 encodes a 200 kDa protein called tuberin.
