Phakomatoses (or "neurocutaneous syndromes")

---

 Phakomatoses / Phakomatosis (or "neurocutaneous syndromes") 

Conditions included are:

• Neurofibromatosis 
• Tuberous sclerosis
• Ataxia telangiectasia
• Sturge-Weber syndrome
• von Hippel-Lindau disease
• Incontinentia pigmenti
• Nevoid basal cell carcinoma syndrome

 Important points commonly asked in various examinations : 

 1. Neurofibromatosis -  inheritance AD

NF1 (Most common phakomatosis) = von Recklinghausen disease	NF2
Mutation - Chromosome 17 : Neurofibromin gene	Chromosome 22  : Merlin gene = schwannomin
Other MCQ points –(findings / associations) Cafe au lait spots Neurofibromas Optic nerve gliomas Lisch nodules (Iris hamartomas) Axillary or inguinal freckling Sphenoid wing dysplasia	Other MCQ points –(findings / associations) Schwannomas (Usually bilateral – 90% ) Meningiomas Ependymomas Mnemonic STEM where T is for TWO (NF2) About 70% of NF2 patients also have skin tumours.

 2. Tuberous sclerosis (Bourneville disease)  - inheritance AD

Triad :

• Mental retardation
• Epilepsy
• Adenoma sebaceum

Other MCQ points : (findings / associations)

• Ash leaf spots
• Shagreen patches (Connective tissue nevi , yellowish, over lumbar region) 
• Systemic hamartomas ( brain , retina , viscera )
• Subependymal giant cell astrocytoma. (near foramen of monro)

 3. Sturge-Weber syndrome (Encephalofacial angiomatosis) 

MCQ points : (findings / associations)

• Naevus flammeus (Port wine stain - on the forehead and upper eyelid of one side of the face )
• Hemangiomas - Choroidal , Meningeal
• Congenital glaucoma
• Epilepsy
• CT scan - Cortical atrophy , Tram track calcifications.

 4. von Hippel-Lindau disease  -inheritance AD

Gene mutation : Chromosome 3p25 (same gene is mutated in Sporadic RCC)

MCQ points : (findings / associations)

• Capillary hemangiomas of retina or optic nerve head
• Hemangioblastoma of cerebellum , spinal cord , medulla or pons.
• Tumours - renal carcinoma and phaeochromocytoma 
• Cysts - kidneys, liver, pancreas, epididymis, ovary and lungs 
• Polycythaemia

---

MedicoNotebook - Founder : DrShiviMudgal , Co-Founder : DrAyushGoel