Autosomal dominant condition, so 50% risk of passing on to offspring and variable penetrance. May be spontaneous mutation.
Diagnosis still essentially clinical: 1988 Consensus is for any 2 of the following:
- 6 or more cafe-au-lait spots (at least “pencil thickness” in diameter?)
- axillary or groin freckling
- 2 or more Lisch nodules – pigmented lesions in iris, may need slit lamp to see. No clinical consequence!
- 2 or more neurofibromas,
- optic pathway glioma (OPG),
- bone dysplasia,
- first-degree family relative with NF1
Plexiform neurofibromas are larger ones with potential to cause visual, hearing, even cardiac problems.
Issues are:
- High blood pressure
- Epilepsy (lesions develop in brain)
- Bone problems including scoliosis
- Effects of neurofibromas in sensitive locations
- Cosmetic appearance, self image
- Cancer (malignant change in neurofibroma but also brain and breast)
- Risk to own children
Ophthalmology review annually in children, every 2 yrs in adults, given risk of optic gliomas.
Family support at https://nervetumours.org.uk/
Clinical trial of selumetinib had beneficial effect on inoperable plexiform fibromas.