Neurocutaneous Flashcards
What is the de novo rate of NF1?
50%
What are the seven criteria for NF1?
2 or more of the following criteria:
- > = 6 cafe-au-lait spots (>5mm prepubertal; >15mm post-pubertal)
- > = 2 neurofibromas of any type; >= 1 plexiform neurofibroma
- > = 2 Lisch nodules
- Freckling in axilla or groin
- Optic glioma
- First degree relative with NF1
- Distinctive bony lesion (dysphagia of the sphenoid bone, dysphagia or thinning of long bone cortex)
What are the nervous system manifestations in NF1?
- Macrocephaly (30-45%)
- Learning disability (30-65%)
- MRI ‘brightspots’ on T2 (UBO
- Headache (9-10%)
*Epilepsy (3.5-7%)
*Cerebrovascular dysplasia (2-6%, e.g. Moya Moya)
What are the tumors seen in NF1?
PNS:
Plexiform neurofibroma
Malignant peripheral nerve sheath tumors (neurofibrosarcomas-10%)
CNS:
Pilocytic astrocytoma (20%)
Optic pathway and hypothalamic predominance (24%)
High grade gliomas in >6yr, or outside optic pathway
Non-CNS (acquired second hit):
Pheochromocytoma (0.1-5.7%)
GI stromal
Glomus tumors
Breast CA
Rhabdomyosarcomas
NE-Carcinoid tumors
Juvenile myelocytic leukemia
When is the risk for growth of neurofibromas in NF1?
Early childhood
Adolescence
Pregnancy
What is the differential diagnosis for NF1?
Legius syndrome (SPRED1 mutations)
Homozygous for HNPCC mutations
NF2/schwannomatosis
Noonan syndrome/LEOPARD syndrome
McCune Albright syndrome
MEN2
Multiple lipomatosis
What is the gene and phenotype for Legius syndrome?
SPRED1 (AD)
CALs, freckling, and macrocephaly
No neurofibromas, Lisch nodules, optic gliomas, osseous lesions
What is the NF1/Noonan phenotype?
Short stature
Webbed neck
Facial dysmorphism
Pulmonary stenosis
What are the facial features of Noonan syndrome?
Epicanthal folds
Ptosis
Downslanting palpebral fissures (95%)
Triangular facies
High nasal bridge
Low-set, posterior rotated ears
Thickened pinnae/helix (90%)
What is Selumetinib?
The drug used in inoperable plexiform neurofibromas
What criteria must be met for Neurofibromatosis type 2?
Must meet one of the following criteria:
- Bilateral vestibular schwannomas (VS)
- First-degree relative with NF2 AND unilateral VS
- First-degree relative with NF2 OR unilateral VS and two of:
-Meningioma, cataract, glioma, neurofibroma
-Schwannoma, cerebral calcification - Multiple meningioma (2 or more) AND two of:
-Unilateral VS, cataract, glioma, neurofibroma, schwannoma, cerebral calcification
What percentage of NF2 is de novo?
50%
What percentage of de novo NF2 mutations are mosaic?
25%
What are the top 3 presenting symptoms in NF2?
Unilateral hearing loss (35%)
Focal weakness (12%)
Tinnitus (10%)
What are the ocular findings in NF2?
Decreased visual acuity in 1/3 of pts.
Retinal hamartoma and epiretinal membrane
Posterior sub-capsular lens opacity
Corneal damage
Intra-orbital tumors
What is the lifetime risk of meningiomas in NF2?
75%
What genes are the cause of SCHWANNOMATOSIS?
SMARCB1
LZTR1
What is the phenotype of SCHWANNOMATOSIS?
Multiple schwannomas, without acoustic tumors
Intracranial, spinal nerve root, peripheral nerve tumors
Pain and neurological manifestations
What percentage of SCHWANNOMATOSIS is familial?
10%
What is the phenotype of Neurocutaneous Melanosis?
Abnormal pigmented nevi
Present at birth
Hydrocephalus
Recurrent seizures
CSF: High protein, Low glucose, melanocytes
Poor prognosis
What is the genetic cause of Neurocutaneous Melanosis?
Most commonly results from an embryonic postzygotic somatic mutation in NRAS
What percentage of TSC is de novo?
2/3
What percentage of TSC is due to germline mosaicism?
~2%
What percentage of TSC is due to mutations in TSC1? TSC2?
19%; 60%
What are the brain findings in TSC?
Cortical tubers (>80%)
Subependymal nodule (~80%)
Subependymal astrocytoma
What are the neurological manifestations in TSC?
Intractable seizures (90-96%), infantile spasms most common
Behavioral and cognitive dysfunction (40-50%)
Autism
What are the major features of TSC?
- Hypomelanotic macules (>3, at least 5mm)
- Angiofibromas (>3) or fibrous cephalic plaque
- Ungual fibromas (>2)
- Shagreen patch
- Multiple retinal harmartomas
- Cortical dysplasias
- Subependymal nodules
- Subependymal giant cell astrocytoma
- Cardiac rhabdomyoma
- Lymphangioleiomyomatosis
- Angiomyolipomas (>2)
What are the minor features of TSC?
- Confetti skin lessions
- Dental enamel pits (>3)
- Intraoral fibromas (>2)
- Retinal achromic patch
- Multiple renal cysts
- Nonrenal hamartomas
What is the phenotype of Sturge-Weber Syndrome?
Facial port wine stain in the V1 distribution of trigeminal nerve associated with leptomeningeal angiomatosis
Seizures (55-90%)
Glaucoma (60%)
DD (55%)
How common is port wine stain in newborns
~0.3%
What is the genetic cause of Sturge-Weber Syndrome?
Somatic mutations in GNAQ
What is the phenotype of Osler-Weber-Rendu syndrome?
Hereditary hemorrhagic telangiectasia (AVMs-most common locations affected are the nose, lungs, brain and liver)
Recurrent nosebleeds
Skin changes begin at puberty
Disease progressively worsens
What are the gene changes in Osler-Weber-Rendu syndrome?
ENG, ACVRL1, SMAD4, GDF2
(90% of cases)
What is the phenotype of Von Hippel-Lindau syndrome?
Tumors and cysts to grow in certain parts of the body, including the brain, spinal cord, eyes, inner ear, adrenal glands, pancreas, kidney, and reproductive tract.
The tumors are usually benign (not cancer), but some may be malignant (cancer).
What is the gene change in Von Hippel-Lindau syndrome?
AD mutations in VHL gene
When do neurofibromas develop in NF1?
Preteen and adolescent years
When do plexiform neurofibromas develop in NF1?
Congenital
