neurocutaneous syndromes

neurocutaneous syndromes

1. nervous sys & skin- ectodermal origin

   • embryological disruption causes neurocutaneous syndromes

2. neurofibromatosis type 1 (NF1)

   • affects 1 in 3000 live births
     • 1/3 have new mutations
   • autosomal dominant, highly penetrant
   • the gene has been IDed
   • diag
     • 2 or more of these criteria
       • 6 or more cafe au lait spots
         • > 5mm in size before puberty
         • > 15mm after puberty
       • > 1 neurofibroma unsightly firm nodular overgrowth over any nerve)
       • axillary freckles
       • optic glioma
         • may cause visual impairment
       • 1 Lisch nodule (harmartoma of iris seen on slit lamp exam)
       • bony lesions from sphenoid dysplasia
         • can cause eye protrusion
       • a 1st degree relative w/ NF1
   • cutaneous features
     • more evident after puberty
     • wide spectrum of involvement
     • neurofibromata
       • appear on course of any peripheral nerve
         • incl cranial nn
           • compression of CN2 or CN8->visual/auditory imp
       • may look unsightly
       • may cause neuro signs
         • if they occur @ a site where a peripheral n passes through a bony foramen
   • megalencephaly
     • w/ LD
     • w/ epilepsy
   • most ppl just have the cutaneous stigmata

3. NF2

   • bilat, acoustic or central
   • less common
   • presents in teen years
   • bilat acoustic neuroma are predominant feature
     • present w/
       • deafness
       • cerebellopontine angle syn
         • CN7 paresis
         • cerebellar ataxia
     • rarely the benign tumours undergo sarcomatous change
   • there may be overlap btw NF1 & NF2
     • NF1 & NF2 can be assoc with
       • MEN syndromes
       • phaeochromocytoma
       • pulmonary hypertension
       • renal artery stenosis w/ hyperetension
       • gliomatous change
         • esp CNS lesions

4. tuberous sclerosis

   • dominantly inherited
     • but up to 70% are new mutations
   • prevalence= 1 in 9000 live births
   • cutaneous features
     • depigmented ash leaf-shaped patches
       • fluoresce under Wood's light (UV light)
     • roughened patches of skin (shagreen patches) usually over the lumbar spine
     • adenoma sebaceum (angiofibromata)
       • in butterfly distribution over bridge of nose & cheecks
       • unusual before 3 years
   • neuro features
     • infantile spasms & developmental delay
     • epilepsy-often focal
     • intellectual impairment
   • severe LD
   • other features
     • fibromata under nails (subungual fibromata)
     • phakomata (dense white areas on the retina)
       • from local degen
     • rhabdomyomata of the heart
       • IDable in early weeks on echo but resolve in infancy
     • polycystic kidneys
   • gliomatous change can occur in the brain lesions
   • autistic features to behaviour when older
   • CT scans
     • detect calcified subependymal nodules & tubers from 2nd yr of life
   • MRI
     • more sensitive & more clearly IDs other tubers & lesions

5. Sturge-Weber syn

   • sporadic disorder
   • a haemangiomatous facial lesion (port wine stain)
     • in distribution of CN5 assoc w/ a similar lesion intracranially
       • ophthalmic division always involved
   • imaging
     • MRI
       • modality of choice now
     • skull x-ray
       • characteristic rail-road track calcification
         • classification of the gyri
   • most severe form
     • epilepsy
       • if intractable and presenting in early infancy
         • hemispherectomy may help
     • LD
     • hemiplegia
   • less severely affected
     • seizures & LD
     • deterioration unusual after 5 years old
   • high risk of glaucoma
     • assess this in neonatal period