TSC1, or Tuberous Sclerosis Complex 1, is a gene located on chromosome 9 that plays a crucial role in regulating cell growth and division. Mutations in the TSC1 gene can lead to the development of tuberous sclerosis, a genetic disorder characterized by the growth of benign tumors in various organs, including the brain, kidneys, and skin. The protein produced by the TSC1 gene, known as hamartin, works in conjunction with another protein called tuberin (produced by the TSC2 gene) to control the mTOR signaling pathway. This pathway is essential for cellular processes such as growth, metabolism, and proliferation, and its dysregulation can contribute to tumor formation.