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Neurocutaneous syndromes — neurofibromatosis, tuberous sclerosis and Sturge-Weber
Neurocutaneous syndromes are genetic diseases in which the skin and nervous system are affected together, because both develop from ectoderm; a small skin sign — a café-au-lait macule, an ash-leaf white macule or a port-wine stain — is often the first clue.
Why it matters in the exam
The exam shows a child with six café-au-lait macules and axillary freckling (NF1), an infant with spasms and white macules seen under a Wood lamp (tuberous sclerosis), or a newborn with a port-wine stain over the forehead and upper eyelid (Sturge-Weber). The question tests the criteria, the gene, the inheritance (autosomal dominant), the complications and the surveillance: annual eye examination and blood pressure in NF1, brain MRI, echocardiography and kidney imaging in tuberous sclerosis, and intraocular pressure and MRI in Sturge-Weber. Remember also the targeted treatments: MEK inhibitors (selumetinib) for plexiform neurofibromas, and mTOR inhibitors (sirolimus and everolimus) in tuberous sclerosis, including topical sirolimus for facial angiofibromas. In the exam also watch for non-skin signs: learning difficulties, autism and epilepsy.
Key points
- Neurocutaneous syndromes affect the skin and nervous system together, and a skin sign is often the first clue.
- NF1 is diagnosed by 6 or more café-au-lait macules, fold freckling, neurofibromas, Lisch nodules and optic glioma.
- Tuberous sclerosis includes ash-leaf macules, angiofibromas, a shagreen patch, seizures and cardiac rhabdomyoma.
- Sturge-Weber is caused by a somatic GNAQ mutation and presents with a port-wine stain in the V1 area, seizures and glaucoma.
- Targeted treatments include selumetinib for plexiform neurofibromas and mTOR inhibitors in tuberous sclerosis.
Summary table
| Syndrome | Skin signs | Gene and inheritance | Complications and surveillance |
|---|---|---|---|
| Neurofibromatosis 1 | 6 or more café-au-lait macules, axillary and inguinal freckling, neurofibromas | NF1 (neurofibromin), autosomal dominant | Optic glioma, Lisch nodules of the iris, scoliosis, hypertension, MPNST; selumetinib for plexiform neurofibroma |
| Neurofibromatosis 2 | Few skin lesions | NF2 (merlin), autosomal dominant | Bilateral vestibular schwannomas, meningiomas, cataract |
| Tuberous sclerosis complex (TSC) | Ash-leaf white macules, facial angiofibromas, shagreen patch, periungual fibromas | TSC1 or TSC2, autosomal dominant | Seizures, autism, cardiac rhabdomyoma, renal angiomyolipoma, LAM; mTOR inhibitors |
| Sturge-Weber | Port-wine stain in the V1 area (forehead and upper eyelid) | Somatic GNAQ mutation, not inherited | Leptomeningeal angioma, seizures, glaucoma; pulsed dye laser |
| Ataxia-telangiectasia | Telangiectasia of the conjunctiva and ears | ATM, autosomal recessive | Ataxia, immunodeficiency, radiation sensitivity and lymphoma risk |
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Sources
- Revised diagnostic criteria for neurofibromatosis type 1 (International Consensus Group), 2021 — Diagnostic criteria
- International Tuberous Sclerosis Complex Consensus Conference recommendations, 2021 — Diagnosis and surveillance
- American Academy of Pediatrics clinical report — health supervision for children with neurofibromatosis type 1, 2019 — Surveillance
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-06. The text may contain errors; when in doubt, check the source.