Hamartomas develop throughout the body in many organs such as the skin, brain, eye, kidney, and heart. Ninety per cent of patients have skin lesions, including hypomelanotic patches called 'ashleaf' spots that can best be visualized under a Woods lamp. Symptoms vary widely depending upon the location and size of the growths. These appear as rhabdomyomas in the heart, angiomyolipomas in the kidneys, bone cysts, and oral fibromas. Other intracranial growths such as subependymal astrocytomas and cortical tubers are evidence of CNS involvement that can interfere with brain function leading to seizures (in 80% of patients) and subnormal intellectual abilities (60-70% patients) as manifested by learning difficulties, subnormal IQs, as well as social and communication difficulties. Hypoplasia of dental enamel with pitting in permanent teeth is seen in the majority of patients. Some progression of tumor size and symptoms may occur. Most hamartomas are benign but renal carcinoma has been reported in some patients.
There is some evidence that the clinical disease is more severe in this type (TSC2) than in type 1 (191100). TSC2 has more hypomelanotic patches and brain tubers. Cognitive defects are more severe. Those with TSC2 mutations also have an earlier onset of seizures and a higher incidence of infantile spasms.