Tuberous sclerosis complex (TSC) is an autosomal dominant disease with an estimated prevalence of about 1: 10000 at birth and about 1: 15 000 by 5 years of age. Tuberin is a large hydrophobic protein. Alternative splicing of the TSC2 mRNA indicates that several different isoforms of tuberin are expressed, according to the tissue and stage of development. When a diagnosis of TSC is made or suspected, cranial imaging is recommended, as over 90% of patients show subependymal nodules, cortical tubers or both. TSC of the lungs, in the form of lymphangioleiomyomatosis (LAM), is rare and almost uniquely present in females. LAM occurs in 1–2% of women with TSC and almost exclusively above 20 years. The most predominant and characteristic ophthalmological sign in TSC is retinal hamartoma, often located in the periphery of the retina of the eye, and thus asymptomatic. About 25% of patients exhibit this sign, which can sometimes be quite important for confirmation of the diagnosis of TSC.