NF1 is one of two genetic disorders classified as Neurofibromatosis. The other is Neurofibromatosis Type 2, or NF2.

One common misconception is that NF2 is simply a more severe version of NF1, but the two are actually distinct disorders with different genetic origins.

• Entirely different genes are responsible for NF1 and NF2. NF1 is caused by mutations in the NF1 gene. Mutations in the NF2 gene, which is located on chromosome 22, are responsible for NF2. To date, researchers have not found links between the biology of these two genes.
• The physical features of NF2 are also different from those of NF1. Features of NF2 include:
  • Acoustic neuromas, which are brain tumors that grow on the nerves leading to the ears. These tumors can impair hearing and cause loss of balance.
  • Other types of brain tumors.
  • Tumors on the spine.
  • Cataracts, which cause clouding of the lens of the eye and eventually lead to blindness. In the general population, cataracts typically develop later in life. People with NF2 can develop cataracts at an early age.

• Both NF1 and NF2 are disorders of the nervous system, and both are characterized by tumor growth on or around different types of nerve cells.
• Both disorders are inherited in a dominant manner.
  • To understand what dominant means, you need to know that all of us inherit two copies of each gene in the human genome. We inherit one copy from our mother and one copy from our father.
  • A dominant disorder is one that arises when an individual inherits just one mutated copy of the gene. The other copy is not mutated.
  • Other disorders are recessive, which means that an individual must inherit two mutated copies of the gene to develop the disorder. Well-known recessive disorders include cystic fibrosis and sickle cell disease.