What is the Difference Between NF1 and NF2?
🆚 Go to Comparative Table 🆚Neurofibromatosis (NF) is a group of genetic disorders that cause tumors to grow along nerves. There are two main types of neurofibromatosis: NF1 and NF2. The key differences between NF1 and NF2 include the symptoms, affected nerves, and genetic causes.
Neurofibromatosis Type 1 (NF1):
- Common symptoms include café-au-lait spots (light brown skin patches), neurofibromas (tumors that can grow on nerves and organs), and Lisch nodules (tiny growths in the iris of the eye).
- NF1 is caused by a mutation in the NF1 gene on chromosome 17, which encodes the protein neurofibromin.
- The condition is characterized by multiple freckles in the armpit or groin area, bone deformities such as scoliosis or bowed legs, and tumors along the optic nerve that may cause vision problems.
- NF1 is more common than NF2, with half of the patients inheriting the mutation from their parents and the other half developing the mutation de novo.
Neurofibromatosis Type 2 (NF2):
- NF2 is characterized by tumors on the eighth cranial nerve, which can lead to hearing loss, headaches, loss of facial control, and balance and walking problems.
- Common symptoms include multiple tumors on the cranial and spinal nerves, as well as hearing loss beginning in the teens or early 20s.
- NF2 is caused by a mutation in a different gene than NF1, although the specific gene is not mentioned in the search results.
- NF2 is much rarer than NF1, and the condition can be bilateral, affecting both auditory nerves and causing hearing loss.
- People with NF2 are also at risk of other tumors arising from the tissue wrapping around the brain and tumors occurring in the deep fluid-filled spaces of the brain and spinal cord (ependymomas).
In summary, the main differences between NF1 and NF2 are the affected nerves, symptoms, and genetic causes. NF1 is characterized by tumors on various nerves and organs, while NF2 primarily affects the auditory nerves.
Comparative Table: NF1 vs NF2
Neurofibromatosis type 1 (NF1) and type 2 (NF2) are neurocutaneous disorders inherited as autosomal dominant genetic syndromes. They share a common name but are distinct in terms of clinical manifestations and genetic factors. Here is a table summarizing the differences between NF1 and NF2:
| Feature | NF1 | NF2 |
|---|---|---|
| Incidence | Accounts for 96% of all neurofibromatosis cases | Accounts for 3% of all neurofibromatosis cases |
| Genetics | Caused by mutations in the NF1 gene located on chromosome 17q11.2 | Caused by mutations in the NF2 gene |
| Clinical Manifestations | Diverse clinical manifestations, including café-au-lait spots, axillary and inguinal freckles, iris hamartomas (Lisch nodules), and various types of tumors | Primarily causes vestibular schwannomas (acoustic neuromas), which can lead to hearing loss, tinnitus, and balance issues |
| Other Features | Plexiform neurofibromas, optic pathway gliomas, and malignant peripheral nerve sheath tumors can also occur | Spinal tumors, most frequently ependymomas, are common, with up to 90% of patients with NF2 being affected |
Some common mutations in NF2 include whole NF1 gene deletions in about 4-5% of individuals with NF1 and truncation of neurofibromin 1 due to alteration of mRNA splicing. There is currently no way to prevent or cure NF1 or NF2, but genetic testing, cytogenetic testing, and prenatal testing can help in identifying and managing these conditions.