It is due to pathogenic DNA alterations in either TSC1 (OMIM 605284) or TSC2 (OMIM 191092) genes and is characterized by benign tumors (hamartomas) in distinct organs, mainly the brain, skin, heart, kidneys, and lungs.1, 2 The TSC1 gene (9q34) encodes hamartin, and TSC2 (16p13.3) codes for tuberin. The gene discussed is TSC2; the disease is hamartoma.