| • | AKA von Recklinghausen disease |
| • | autosomal dominant; chromosome 17 |
| • | most common form of NF (~85% cases) |
| • | pathogenesis: NF-1 gene product = neurofibromin 1 |
| • | at least one of the functions of neurofibromin appears to be regulation of the RAS oncogene |
skin:
| • | post-pubertal: 6 or more café au lait spots (>1.5cm) |
| • | pre-pubertal: 6 or more café au lait spots (>0.5cm) |
| • | Crowe’s sign: axillary freckling ~ pathognomonic (= small café au laits) |
| • | begin to appear at puberty; |
| • | ddx: intradermal nevus, skin tag |
| • | “button hole” sign = on compression, can be invaginated into what feels like a defect in the skin |
| • | clinically: “bag of worms” |
| • | an elongated tumor that occurs along the course of peripheral nerves |
eyes:
| • | Lisch nodules = iris hamartomas (~ iris freckles); |
| • | present in 100% NF1 patients by age 20 (90% by age 6) |
| • | optic glioma (and other astrocytomas) |
neoplasia: increased pheochromocytoma incidence
CNS: learning disabilities, seizures
follow up and treatment:
| • | ketotifen (2 to 4 mg/day) may help minimize itch, pain, tenderness associated with neurofibromas |
| • | in asymptomatic patients, clinical follow-up is more beneficial than systemic investigations (e.g. imaging, 24-hour urine catecholamines) |
| • | routine clinical exam should look for hypertension (renal artery stenosis or pheochromocytoma), history of flushing |
| • | exception – in children consider MRI of optic pathways for baseline and to screen for possibly evolving optic gliomas |
| • | primary care, ophthalmology, neurology |
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