USMLE Step 1 · Biochemistry & Genetics

Tuberous sclerosis vs Sturge-Weber and Von Hippel-Lindau syndromes

How to tell Tuberous sclerosis and Sturge-Weber and Von Hippel-Lindau syndromes apart when a board question makes them look alike.

Fastest separator

Tuberous sclerosis is hamartomas with ash-leaf/seizures; Sturge-Weber is port-wine/leptomeningeal angioma; VHL is hemangioblastoma plus RCC/pheochromocytoma.

Side by side

Tuberous sclerosisSturge-Weber and Von Hippel-Lindau syndromes

Key clue

Tuberous sclerosis causes seizures, intellectual disability, cortical tubers, subependymal giant cell astrocytoma, ash-leaf spots, shagreen patches, facial angiofibromas, renal angiomyolipomas, and cardiac rhabdomyomas.

Sturge-Weber causes facial port-wine stain in V1 distribution, leptomeningeal angiomas, seizures, and tram-track calcifications; VHL causes hemangioblastomas, renal cell carcinoma, pheochromocytoma, and cysts.

Mechanism

TSC1/TSC2 mutations dysregulate hamartin/tuberin inhibition of mTOR, producing hamartomas in multiple organs.

Sturge-Weber is usually somatic mosaic GNAQ-driven leptomeningeal/capillary malformation; VHL loss increases HIF signaling and drives hemangioblastomas, renal cell carcinoma, pheochromocytoma, and cysts.

Labs and tests

Ash-leaf macules, cortical tubers, renal angiomyolipoma, and cardiac rhabdomyoma support tuberous sclerosis.

Port-wine stain with leptomeningeal angioma supports Sturge-Weber; retinal/cerebellar hemangioblastoma plus RCC supports VHL.

The trap

All are neurocutaneous or tumor-prone syndromes, so skin lesion type and tumor pattern separate them.

The repair move

For neurocutaneous syndromes, attach the skin lesion to the brain and visceral tumor pattern.

Try a free question

Core

A 4-year-old child has a long history of generalized tonic-clonic seizures, hypopigmented 'ash-leaf' macules on the trunk, facial angiofibromas in a malar distribution, intellectual disability, and rough leathery skin patch in the lumbar region (shagreen patch). Brain MRI shows cortical tubers and a subependymal giant cell astrocytoma. Which condition is most likely?

Show answer and explanation

Answer: A. Tuberous sclerosis complex. Tuberous sclerosis (TSC1/TSC2 mutations, autosomal dominant) causes mTOR hyperactivation with hamartomas in multiple organs: ash-leaf hypopigmented macules, facial angiofibromas, shagreen patch, cortical tubers, subependymal giant cell astrocytoma (SEGA), cardiac rhabdomyomas, renal angiomyolipomas. Treat with mTOR inhibitors (sirolimus, everolimus).

Why the other choices are tempting

B. Sturge-Weber syndrome features a port-wine stain in the V1 trigeminal distribution with ipsilateral leptomeningeal angioma and tram-track calcifications, not ash-leaf macules with angiofibromas.
C. von Hippel-Lindau disease features hemangioblastomas of CNS/retina, renal cell carcinoma, and pheochromocytoma, not the TSC cutaneous picture.
D. NF1 features cafe-au-lait macules and Lisch nodules, not hypopigmented ash-leaf macules.
E. Cowden syndrome (PTEN mutations) features multiple hamartomas with breast/thyroid/endometrial cancer risk, not the TSC cutaneous and CNS picture.

Flashcards

Tap a card to flip it.

What clue supports Tuberous sclerosis?

Choose Tuberous sclerosis when the stem gives this pattern: Tuberous sclerosis causes seizures, intellectual disability, cortical tubers, subependymal giant cell astrocytoma, ash-leaf spots, shagreen patches, facial angiofibromas, renal angiomyolipomas, and cardiac rhabdomyomas.

What clue supports Sturge-Weber and Von Hippel-Lindau syndromes?

Choose Sturge-Weber and Von Hippel-Lindau syndromes when the stem gives this contrasting pattern: Sturge-Weber causes facial port-wine stain in V1 distribution, leptomeningeal angiomas, seizures, and tram-track calcifications; VHL causes hemangioblastomas, renal cell carcinoma, pheochromocytoma, and cysts.

Quick answers

What is the fastest way to tell Tuberous sclerosis from Sturge-Weber and Von Hippel-Lindau syndromes?