Pronounced neuro-fibroma-tosis and commonly referred to as NF.
Neurofibromatosis (NF) is an umbrella name for 3 distinct complex genetic disorders that share a common manifestation: tumour growth in the tissues that surround nerves. Most of these tumours are benign, although occasionally they can become malignant. NF may also cause additional complications such as disfigurement, bone deformities and learning disabilities. Neurofibromatosis equally affects males and females of all ethnic groups. Although more common than cystic fibrosis, Duchenne muscular dystrophy, Huntington’s disease and Tay-Sachs disease combined, neurofibromatosis is largely unknown and misunderstood in the general population. The 3 types of neurofibromatosis are:
- Neurofibromatosis Type 1 (NF1): the most common form affecting approximately 1 in 3,000 to 4,000 births.
- Neurofibromatosis Type 2 (NF2): the less common form, affecting approximately 1 in 40,000 births.
- Schwannomatosis appears to occur as often as NF2.
NF1 is the most common form of neurofibromatosis, causing developmental changes in the nervous system, skin, bones, and other tissues. NF1 is commonly characterized by the presence of café-au-lait spots, auxiliary freckling, cutaneous neurofibromas (tumours) and Lische nodules (freckles on the iris of the eye). Half of the cases of NF1 result from spontaneous genetic alteration, while the remainder of the cases are inherited from one or both of the parents.
NF1 affects each person differently. Some people are quite severely affected and require increased medical treatment while others are quite mildly affected and may not experience any impacting symptoms of the disorder. Each individual with NF1 – even those in the same family – can be affected to a very different extent. Overall, it is estimated that about half of the people with NF1 are mildly affected by the disorder. While it is very unlikely that any one person diagnosed with NF will experience all of the associated complications, it is difficult to predict the severity or progression of the disorder in any individual case.
NF2, also called Bilateral Acoustic Neurofibromatosis, is very different from NF1 and a much rarer disorder characterized by the growth of vestibular schwannomas, tumours affecting the auditory nerves and sometimes associated with tumours of the central nervous system. NF2 affects approximately 1 in 40,000 people.
Schwannomatosis is the most recently recognized form of neurofibromatosis, characterized by the growth of multiple schwannomas anywhere except on the vestibular nerve. This disorder appears to occur as often as NF2.