Etiology and Pathogenesis
Tuberous sclerosis is a disorder of cellular differentiation and proliferation.
Two TSC genes have been identified; one is on chromosome 9q34 (TSC1) and the other is on chromosome 16pl3 (TSC2) Clinical features and presentation
Cutaneous findings include hypomelanotic macules, facial angio fibromata, ungual fibromas and the shagreen patch.
- The earliest detectible abnormalities in TS are hypopigmented macules (Ash-leaf spot) and rhabdomyomas, both of which are often present at birth.
- Facial angio fibromata are found in 75% of all patierils with tuberous sclerosis.
- Ungual fibromas are fleshy lesions that occur beneath the nails- They occur in only 25% of affected persons, arise in early adulthood, and are fairly specific for tuberous sclerosis. A shagreen patch is a cluster of connective tissue hamartoma that appears as an irregularly shaped plaque with a green to red hue, and is commonly found on the patient's back or flank.
Central nervous system lesions of tuberous sclerosis include cortical hamartomas (tubers), focal cortical dysplasia, subependymal nodule, subependymal giant cell astrocytoma, and relinai phakoma (astrocytomas).
Renal involvement exists in up to 80% of patients and may lead to significant morbidity and mortality. Angiomyolipomas are by far the most frequent renal lesion, and the risk of hemon-hagic complications appears to be related.