• Tuberous sclerosis (TS) is a dominantly inherited disorder characterized by seizures, developmental delay, and specific skin lesions. Hypopigmented maculae that occur in 80% of patients with TS have become important for the clinical diagnosis of TS in young children. These lesions are claimed to be present from birth, in contrast with other dermatologic manifestations of TS that usually appear much later. We studied seven children in whom hypopigmented maculae appeared months to years after repeated negative skin examinations. Our findings emphasized that the absence of hypopigmented maculae in young children does not preclude their later appearance nor rule out the diagnosis of TS. The need for repeated skin examinations in infants and children with suspected TS or with seizures and/or mental retardation of unknown cause is apparent.