Causes of neurofibromatosis type 2
Neurofibromatosis type 2 (NF2) is caused by a faulty gene. If the NF2 gene is faulty, it leads to uncontrolled growths (tumours) developing in the nervous system.
In half of all cases of NF2, the faulty gene is passed from a parent to their child. Only 1 parent needs to have the faulty gene for their child to be at risk of developing the condition.
If either the mother or father has the faulty gene, there's a 1 in 2 chance that each child they have will develop NF2.
In other cases, the faulty gene appears to develop spontaneously. It's unclear why this happens.
If you have a child who develops NF2 spontaneously, it's highly unlikely any further children you have will also develop the condition. However, a person who develops NF2 spontaneously can pass the condition to their children.
Mosaic NF2
About 1 in 3 people with NF2 have a form of the disease called mosaic NF2. The symptoms of mosaic NF2 are milder and often restricted to a certain area or side of the body.
People with mosaic NF2 have lower than the usual 50% risk of having a child with NF2. However, if their child does have NF2, it will be the more common type and not mosaic NF2.