Neurofibromatosis type 2
Neurofibromatosis type 2 (NF2) is a disorder characterized by the development of noncancerous tumours along the nerves called schwannomas, which nearly always occur on the hearing and balance nerves (vestibular schwannomas-VS). Most NF2 sufferers develop VS on both sides leading to balance problems and eventually total deafness. Schwannomas on other nerves in the head and spine and elsewhere in the body can cause loss of muscle function and sensation with many NF2 affected people ending up in a wheelchair. The second commonest tumour in NF2 is a noncancerous tumour on the lining of the brain and spinal cord called a meningioma. This too can lead to loss of normal function including headaches and seizures. Finally a tumour within the spinal cord called an ependymoma affects around 20-40% of people but are usually non progressive. NF2 is a life spoiling life limiting condition.
NF2 is an inherited genetic condition caused by a fault in one copy of the NF2 gene on chromosome 22.
NF2 is inherited from an affected parent in about 40% of cases. In the remainder the NF2 gene change starts with that person. This is either in all their cells (65-70%) indicating that the change was present in the egg or sperm that made their first cell at conception or in only some of their cells indicating the gene fault occurred during development as an embryo (called mosaicism). Mosaic NF2 is milder as not all cells are affected and the likelihood of passing NF2 down to children is reduced from the usual 50%. Identifying the underlying gene fault is also helpful in assessing the potential severity of the condition starting with testing of tumour in isolated cases rather than blood if possible.
Screening in NF2 can start with testing of unaffected relatives before symptoms for the family gene fault. Thereafter screening is generally based on the current problems but will usually mean at least an annual head MRI scan and 3 yearly spinal MRI. Treatments include surgical removal of tumours, drug treatments with bevacizumab for rapidly growing schwannomas and in selected cases targeted radiation treatments (not in childhood).
Endorsed by ERN GENTURIS*
* ERN GENTURIS uses AGREE II as a tool for the endorsement of guidelines. The quality of the guideline is evaluated through assessing the rigor and transparency of the guideline development process. The content of the guideline is not evaluated, although selection of the guideline for endorsement includes expert opinion on the usefulness of the content of the guideline.