Neurofibromatosis type 2 (NF2)
A diagnosis of neurofibromatosis type 2 (NF2) comes with many questions and concerns, both for young adults and their families. Although the majority of people with NF2 lead normal lives, there are still many aspects of the disorder that are difficult to predict.
It may comfort you to know that in the Neurofibromatosis Program at Children’s Hospital Boston, we have already helped thousands of children and young adults successfully manage their NF. Our compassionate, experienced clinicians are here to help you every step of the way.
What is NF2?
NF2 is a genetic disorder characterized by certain types of tumors that form within a person’s body or brain.
The most common types of tumors associated with NF2 are:
- Vestibular schwannoma: also called an acoustic neuroma, a vestibular schwannoma is a benign (non-cancerous) tumor that develops on the eighth cranial nerve (a nerve in the inner ear responsible for hearing and balance).
- Meningioma: usually benign, a meningioma is a type of tumor that develops from the meninges (the membrane that surrounds the brain and spinal cord). Meningiomas may cause seizures, hemiparesis (weakness on one side of the body), changes in vision and headaches that worsen over time.
- Ependymoma: a type of brain tumor that develops from ependymal cells that line the ventricles (fluid-filled spaces in the brain) and the central canal within the spinal cord. These tumors often cause problems such as numbness, weakness and pain. Ependymomas have a 50-percent cure rate.
Are there other types of NF?
Yes. Besides NF2, there are two other distinct forms of neurofibromatosis: neurofibromatosis type 1 (NF1) and schwannomatosis.
What is neurofibromatosis type 1 (NF1)?
NF2 may often be confused with NF1. Like NF2, NF1 is also a genetic disorder characterized by the presence of tumors that form along nerves in the body. However, the disorders are caused by two different genes that are located on two different chromosomes. It’s extremely rare that someone would have both NF1 and NF2. Read more about NF1.
Here are some notable clinical differences between NF1 and NF2:
- NF2 is more rare than NF1, which affects 1 in every 3,500 births.
- Symptoms of NF2 are typically detected between the ages of 18 and 24 years, while NF1 is diagnosed in infancy or early childhood.
- In NF2, benign tumors called schwannomas grow on nerves throughout the nervous system and often cause impaired hearing and vision. In NF1, benign tumors called neurofibromas cover the peripheral nerve and, similarly, may cause pain or specific neurologic symptoms. Because one type of neurofibroma commonly grows on or close to the skin, there may also be skin changes that range from mild to severe.
- NF2 is caused by a mutation on chromosome 22 and involves a protein called merlin, which is thought to be involved in cell shape and structure. NF1 is caused by a mutation on chromosome 17 and involves a protein called neurofibromin, which relates to cell growth and cell division.
- Individuals with NF2 do not have learning disabilities, a complication that is very commonly seen in people with NF1.
What is schwannomatosis?
Schwannomatosis is an extremely rare form of NF that affects about 1 in every 40,000 individuals. Although schwannomatosis shares some clinical similarities with the other forms of NF, it is a separate disorder.
Here are important distinguishing features of schwannomatosis:
- It is a genetic disorder, but unlike NF1 and NF2, doesn’t have a clear pattern of inheritance. The chance of an affected parent passing schwannomatosis on to their child is 15 percent, compared to 50 percent in NF1 and NF2.
- Schwannomatosis is characterized by the presence of multiple schwannomas (benign tumors) on the cranial, spinal and peripheral nerves. However, unlike with NF2, people with schwannomatosis do not develop vestibular schwannomas and do not experience impaired hearing.
- If a person presents with multiple schwannomas, the possibility of NF2 must excluded before a diagnosis of schwannomatosis is given. Having no evidence of vestibular tumors or family history of NF2 are two diagnostic criteria used for making this distinction.
Are there any medical complications associated with NF2?
Because NF2 affects the nervous system, the most complications involve problems related to vision, hearing, and balance. Numbness or weakness in the face, arms or legs may also occur. However, there is no evidence that NF2 causes intellectual and learning disabilities, which are very common in individuals with NF1.
What caused my child to get NF2?
In 50 percent of cases, NF2 is inherited from a parent:
- During conception, each parent passes on a copy of the NF2 gene to the embryo. Since NF2 is an autosomal dominantgenetic disorder, the child will inherit the disorder if just one of these genes has a mutation.
- This means that with each pregnancy, parents who are affected by NF2will themselves have a 50 percent chance of passing it on to their child.
- NF2 affects people of all races, sexes and ethnicities equally.
In the other 50 percent of cases, NF2 occurs as a result of a spontaneous mutation:
- A spontaneous mutation occurs when there is a sudden change in genetic material at the time of conception.
- Spontaneous mutations occur in situations where there is no prior family history of NF.
Is there a difference between inherited NF2 and NF2 that occurs from a spontaneous mutation?
No. Aside from its origins, there is no difference between inherited NF2 and NF2 that was caused by a spontaneous mutation.
Did I do anything to cause my child’s NF2?
No, there’s no evidence suggesting that NF2 is caused by environmental factors or something the mother did (or didn’t do) during pregnancy.
Signs and symptoms
When do symptoms of NF2 present?
NF2 is usually detected in early adulthood, with the average age of symptom onset being around 20 years.
What are the first signs of NF2?
Most NF2 tumors grow on the eighth cranial nerve. Located in the inner ear, the eighth cranial nerve is responsible for sending information on both sound and balance to the brain.
As a result, the first symptoms of NF2 are usually caused by the nerve’s impairment:
- hearing loss
- ringing in the ears (called tinnitus)
- problems with balance, beginning in the teens or early twenties
Other symptoms of NF2 may include:
- facial weakness
- changes in vision
- back pain (caused by spinal cord lesions)
- skin changes (caused by schwannomas on the skin, which is more common in children)
Are symptoms of NF2 progressive?
Although it’s almost impossible to predict exactly how NF2 will progress, vestibular schwannomas grow slowly and usually cause balance and hearing to deteriorate over time. Fortunately, there are surgical interventions that can preserve hearing. Visit our Treatment tab to learn more about these options.
Questions to ask your doctor
A diagnosis of NF2 comes with a lot of questions and concerns, for both patients and their families. During your initial appointments with the doctor, it can be easy to become overwhelmed with information and forget what you wanted to ask.
Many parents and young adults find it helpful to write down questions beforehand or jot them down as they arise. That way, when you talk to the doctors, you can be sure that all of your concerns are addressed.
Some questions you might want to ask include:
- How can the symptoms of this disorder be managed?
- What are the options for surgical intervention?
- What is the long-term treatment plan?
- What resources can you point me to for more support and information?