What is neurofibromatosis type 2 (NF2)?
NF2 is a rare, inherited disorder which affects about 1 in 25,000 people; it is caused by a genetic mutation (a change in the genetic message). The disorder may be passed down by a parent, or the change in the genetic message may occur at the time of conception.
NF2 is characterised by benign tumours called vestibular schwannomas. They are made up of schwann cells which are normal cells found in the nervous system. These tumours form on the eighth cranial nerves, which are involved in hearing and balance.
What are some of the other features of NF2?
- Schwannomas may also appear on other cranial nerves, spinal nerves, nerves to the arms and legs, and on the skin. They may be seen as bumps on or under the skin, and they are sometimes smooth and shiny.
- Benign tumours called meningiomas may form on the protective linings of the brain or spinal cord.
- Tumours called ependymomas may form in the brain or spinal cord.
- Cataracts and visual problems may also develop.
- The nerves which supply the fingers and toes can be affected (the peripheral nerves). In these cases people may experience numbness or weakness in these areas (peripheral neuropathy).
How is NF2 diagnosed?
NF2 is diagnosed when there are:
Two vestibular schwannomas
A family history of NF2 and a one-sided vestibular schwannoma
Two or more of the following:
- Childhood cataracts
- Development of a schwannoma in any part of the body
- Glioma (a tumour in the brain)
- Meningioma (a tumour in the protective covering of the brain)
The other way of diagnosing NF2 is by doing a genetic test to look for an NF2 mutation in blood. Sometimes this is carried out in people who have an affected parent and are at risk of having NF2 but don’t yet have symptoms The test is carried out by regional genetics units or by the specialist NF2 teams. Once NF2 is diagnosed a referral is made to the specialist NF2 team.
When do symptoms appear?
- They may be present in childhood – children present with skin tumours, neurological symptoms from brain meningiomas, spinal tumours or cataracts but vestibular schwannoma is unusual in young children.
- Symptoms are most often noted around the age of 18 – 22 years.
What are the symptoms of NF2?
Symptoms may include:
- The most common symptom is hearing loss or ringing in the ears (tinnitus)
- Balance disturbances
- Weakness or numbness in one or more limbs
- Skin tumours
- Visual problems
What does the future hold for people with NF2?
Every person with NF2 is different and the progression of the symptoms and site of the tumours vary from person to person.
What is the treatment for NF2?
If you are diagnosed with NF2, the best way to manage the condition is to attend a specialist NF2 clinic. It is likely that you will be referred to one of the specialist centres below for assessment and management:
- Guy’s & St Thomas’ Hospital in London
- Addenbrooke’s Hospital in Cambridge
- Central Manchester University Hospitals
- Oxford Radcliffe Hospital
You should attend a specialist clinic every year, or more often if your symptoms are severe, so the team of doctors and other specialists can evaluate your progress and assess your quality of life.
Regular investigations include:
- Magnetic resonance imaging, (MRI), to detect and monitor tumours
- Hearing tests to monitor any hearing loss
- Eye tests to detect any cataracts (cloudy patches on the eye) or changes in vision
Vestibular schwannomas may become large enough to press on other nearby structures, or in some cases it may be necessary to remove the tumours to prevent them causing further damage. The timing and type of surgery varies and is tailored to individual need.
Some vestibular schwannomas may be treated with a drug called Avastin or with radiosurgery. The type of treatment will be discussed with you by the specialist team.
The eighth cranial nerves are very close to the facial nerve, and a vestibular schwannoma may sometimes interfere with the functioning of the facial nerve and cause weakness, resulting in facial palsy.
Surgery for other tumours may be carried out in order to relieve symptoms, or to treat pressure on surrounding structures in the brain or spinal cord.
Will NF2 affect my hearing?
If you have NF2, your hearing may become a problem, and learning to lip read may be useful. Below are some more options for managing hearing loss:
- The use of hearing aids
- A special hearing aid called an ABI (auditory brain implant) can benefit people with NF2. The surgeon will remove the vestibular schwannoma from your auditory nerve which connects the ears to the brain. Electrodes will then be implanted in the part of the brain that processes sound information. The electrodes will be connected to a small sound processor chip that is placed outside your ear. The chip captures the sound waves as they enter your ear and converts them into electrical impulses which are transmitted to the electrodes. The ABI takes over the work of your auditory nerves; it may improve your hearing and may make lip reading easier.
- A cochlear implant may be helpful if hearing is declining but the eighth cranial nerve (auditory nerve) has been preserved. This is most commonly after radiosurgery as it is rare to be able to preserve this nerve during surgery. It is a tiny device which is placed in the inner ear (or cochlea) and processes electronic signals from sound waves to the auditory nerve which are then decoded by the brain into meaningful sounds.
FPUK Associated Articles:
Last reviewed: 07-12-2017 || Next review due: 07-12-2020