Neurofibromatosis 1 (NF1) is a common, inherited autosomal dominant disease
The birth incidence is between 1 in 2,500 and 1 in 3,000, with about half being the first in their families to be affected.
Diagnostic criteria are that you need two or more of the following:
- 6 or more cafe au lait macules (>0.5 cm in children and 1.5cm in adults)
- 2 or more cutaneous/subcutaneous neurofibromas or 1 plexiform neurofibroma
- axillary or groin freckling
- optic pathway glioma
- 2 or more Lisch nodules
- bony dysplasia (sphenoid wing dysplasia, bowing of long bone +/- pseudarthrosis
- parent or child with NF1
Patients with NF1 are at risk of a number of problems including optic pathway gliomas, CNS tumours, hypertension and congenital heart disease.
Orthopaedic problems include:
- bowing of long bones +/- pseudarthrosis
- benign tumours (neurofibroma, glomus tumours)
- malignant tumours (10% lifetime risk of malignant change in plexiform neurofibromas (to malignant peripheral nerve sheath tumour), optic pathway gliomas, cerebral gliomas, phaeochromocytoma, rhabdomyosarcoma, juvenile myelomonocytic leukaemia, breast cancer in women)