0 Phakomatoses (or "neurocutaneous syndromes")

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 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

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