Neurofibromatosis (NF) is a genetic disorder that affects the bone, soft tissue, skin and nervous system. It is classified into 2 distinct types, neurofibromatosis 1 (NF1) and neurofibromatosis 2 (NF2). NF1 occurs in about 1 in 3000 births whilst NF2 only occurs in about 1 in 50,000 births.
NF1, also known as von Recklinghausen disease, is characterised by the presence of:
- 6 or more cafe-au-lait spots (defined oval-shaped light brown patches greater than 0.5cm in diameter)
- Multiple neurofibromas (tumours on, under, or hanging off the skin)
- Freckling (under the armpits and areas of skin folds such as the groin)
- Lisch nodules (tiny tumours on the iris of the eye)
NF2, also known as bilateral acoustic neurofibromatosis, is characterised by multiple tumours and lesions on the brain and spinal cord. Tumours growing on the auditory nerves that lead to hearing loss is usually the first symptom of the disease. Often this is not apparent until the late teens or early 20's.
NF1 and NF2 occur as a result of defects in different genes . NF1 is caused by a mutation on a gene located on chromosome 17 and NF2 on chromosome 22. The mutated gene can be inherited from a parent who has NF or in some cases you could be the “founder” of a spontaneously mutated gene. A parent with NF has a 50% chance of passing the gene on to each of their children.
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