Neurofibromatosis type 2 (NF2)
Unlike other genetic disorders, neurofibromatosis type 2 (NF2) typically isn’t diagnosed until the late teens or early adult years. At Children’s Hospital Boston, we know that forming an accurate diagnosis as soon as symptoms present is the first step to effective treatment.
Can NF2 be diagnosed during pregnancy?
If a parent has NF2 and a known mutation, genetic testing can be performed to determine if the baby has inherited the same mutation.
Prenatal diagnosis of NF2 can be done with 65-percent accuracy through:
- chorionic villus sampling (CVS): CVS is used in situations where there is a known family history of a certain genetic disorder.In this procedure, a sample of chorionic villus cells is taken from the placenta. Since chorionic villi are made up of the same genetic material as the baby, they can be used to test for single gene disorders as well as chromosomal abnormalities. CVS is typically done in the 10th to 12th week of pregnancy.
- amniocentesis: In this prenatal diagnosis method, a needle is inserted into the amniotic sac that surrounds the baby and a sample of amniotic fluid is removed. The amniotic fluid contains cells that can be used for genetic testing. Amniocentesis is usually performed between the 15th and 18th weeks of pregnancy.
When is NF2 diagnosed in individuals who don’t receive prenatal testing?
The age at which a given person is diagnosed with NF2 varies depends on the individual. The average age for diagnosis is 28 years. However, more severe cases of the disorder will be detected earlier than in individuals who show milder symptoms. In familial cases of NF2, if the parental mutation is known, the child can be tested at any age.
How is a diagnosis of NF2 made?
In order to have a confirmed diagnosis of NF2, an individual must have:
- a bilateral vestibular schwannoma (affecting both ears)
- a first-degree family relative who has NF2 AND a unilateral vestibular schwannoma (affecting one ear) that presents before the age of 30 years
a first-degree family relative who has NF2 AND any two of the following:
- one of two types of cataracts seen in children: the juvenile posterior subcapsular lenticular opacity or the juvenile cortical cataract (these are seen only by the ophthalmologist)
Doctors may use a magnetic resource-imaging scan (MRI) to look for vestibular schwannomas or other tumors associated with NF2, especially if there is a family history of the disorder. Individuals without a family history but suspected to have NF2 are evaluated in a similar way with imaging studies and regular hearing evaluations.
If an individual meets the diagnostic criteria for NF2, the doctor might also use genetic testing to confirm the diagnosis. However, these testsoften aren’t necessary to confirm a diagnosis.
How do I know if I should be tested for NF2?
Tell your doctor if you or your child experiences hearing loss, ringing in the ears and problems with balance that begin around age 18 to 24. Since these are usually the first symptoms of NF2, your pediatrician may recommend that you schedule an evaluation with our Neurofibromatosis Program.