A 30-year-old woman presents with new-onset seizures. CT head shows multiple calcified nodules in the brain parenchyma and subcortical region. She has a history of seizures since adolescence and has multiple facial angiofibromas. The most likely underlying genetic mutation involves which gene?

• A NF1 on chromosome 17
• B NF2 on chromosome 22
• C TSC1 on chromosome 9 ✓
• D VHL on chromosome 3

Explanation

This describes tuberous sclerosis complex (TSC), characterized by cortical tubers, subependymal nodules, seizures, facial angiofibromas, and intellectual disability. TSC is caused by mutations in TSC1 (hamartin, chromosome 9) or TSC2 (tuberin, chromosome 16), which activate the mTOR pathway. NF1 causes neurofibromas and café-au-lait spots. NF2 causes bilateral vestibular schwannomas. VHL causes hemangioblastomas and renal cell carcinoma.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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