Both sporadic and inherited LAM result from loss-of-function mutations in the tuberous sclerosis complex 1/2 (TSC1/TSC2) genes, resulting in constitutive activation of the mechanistic target of rapamycin (mTOR) pathway, specifically mTOR complex 1 (mTORC1) (10–12). The gene discussed is MTOR; the disease is lymphangioleiomyomatosis.