Welcome to the Rare Classroom, a new series from Patient Worthy. Rare Classroom is designed for the curious reader who wants to get informed on some of the rarest, most mysterious diseases and conditions. There are thousands of rare diseases out there, but only a very small number of them have viable treatments and regularly make the news. This series is an opportunity to learn the basics about some of the diseases that almost no one hears much about or that we otherwise haven’t been able to report on very often.

Eyes front and ears open. Class is now in session.

In recognition of World NF2 Awareness Day on May 22, the rare disease that we will be learning about today is:

Neurofibromatosis Type 2

Also called multiple inherited schwannomas, meningiomas, and ependymomas (MISME) syndrome.

What is Neurofibromatosis Type 2?

• Neurofibromatosis type 2 is a genetic disorder that can appear randomly or be inherited
• The disease triggers benign tumors impacting the peripheral nerves, brain, and spinal cord
• The principal characteristic of neurofibromatosis type 2 is the appearance of bilateral benign brain tumors affecting the nerve sheath of cranial nerve VIII
• The disease is most often diagnosed in early adulthood (20s or 30s), when the benign tumors are likely to have developed to a size that symptoms become noticeable
• Prevalence of neurofibromatosis type 2 is around 1 in 35,000 births

How Do You Get It?

• Neurofibromatosis type 2 is the result of inactivation mutations impacting the NF2 gene. This gene is found at 22q12.2 on chromosome 22.
• Around half of cases are believed to be inherited and half appear spontaneously, as a de novo mutation
  • Research has identified genotype-phenotype relationships between different types of mutations
  • For example, frameshift and nonsense mutations have worse outcomes, and missense mutations have better outcomes

What Are the Symptoms?

• Symptoms of neurofibromatosis type 2 vary depending on the location, presence, and growth rate of the tumors that are present
• The tumor types most often associated with this disorder include ependymomas, vestibular schwannomas, and meningiomas
• Symptoms of neurofibromatosis type 2 include:
  • Glaucoma
  • Seizures
  • Tinnitus
  • Balance issues
  • Hearing and vision loss
  • Numbness and weakness in the limbs

How Is It Treated?

• Treatment for neurofibromatosis type 2 often involves surgery
• Acoustic neuromas, in particular, are often removed, with multiple approaches that vary depending on the overall health condition of the patient, tumor size, and hearing ability
• There are no approved medications for treating tumors in the disease; however, studies of bevacizumab have shown benefits for some patients
• Hearing loss is usually treated with cochlear implants or auditory brainstem implants
• Prognosis is impacted by the age of onset, numbers of tumors, and the mutation present

Where Can I Learn More???

• Learn more about this disease from NF2 BioSolutions.
• Check out our cornerstone on this disease here.