Neurocutaneous Syndromes (Phakomatoses)
What You'll Learn
What You'll Learn
| Disease |
Inheritance |
Gene / Protein |
Chromosome |
Key Features |
| NF1 |
AD |
NF1 / neurofibromin |
17q11.2 |
Café-au-lait macules, neurofibromas, optic gliomas, Lisch nodules |
| NF2 |
AD |
NF2 / merlin (schwannomin) |
22q12.2 |
Bilateral vestibular schwannomas, meningiomas, ependymomas |
| TSC |
AD |
TSC1 / hamartin; TSC2 / tuberin |
9q34; 16p13.3 |
Cortical tubers, SEGA, angiofibromas, cardiac rhabdomyomas |
| VHL |
AD |
VHL / pVHL |
3p25.3 |
Hemangioblastomas, renal cell carcinoma, pheochromocytoma |
| Sturge-Weber |
Sporadic (somatic) |
GNAQ (somatic mosaic) |
9q21.2 |
Port-wine stain (V1), leptomeningeal angiomatosis, seizures, glaucoma |
| Ataxia-Telangiectasia |
AR |
ATM |
11q22.3 |
Cerebellar ataxia, telangiectasias, immunodeficiency, elevated AFP |
Associated Tumors
| Tumor |
Key Points |
| Optic pathway glioma |
Most common CNS tumor in NF1 (~15%); pilocytic astrocytoma (WHO grade I); often asymptomatic; screen with ophthalmologic exam (NOT routine MRI in asymptomatic) |
| Neurofibroma |
Benign peripheral nerve sheath tumor; cutaneous (most common), subcutaneous, or plexiform types |
| Plexiform neurofibroma |
Diffuse, infiltrative along nerve; pathognomonic for NF1; ~10% risk of malignant transformation to MPNST |
| MPNST |
Malignant peripheral nerve sheath tumor; lifetime risk 8–13% in NF1; suspect if rapid growth, pain, new neurological deficit |
| Brainstem glioma |
More common in NF1 than general population; often indolent |
| Pheochromocytoma |
~1–5% of NF1 patients; cause of secondary hypertension |
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