Neurofibromatosis Type 1 Diagnosis

Diagnosis of Neurofibromatosis Type 1 (NF1) should always be made or confirmed by an NF expert as there are some similar genetic conditions which can be confused for NF1. The diagnosis of NF1 is made by a doctor who is trained to recognize the features of NF1 using a physical exam and sometimes imaging studies or an eye exam.

The diagnosis of NF1 requires that two or more of the following characteristics be present:

  • Six or more café-au-lait macules (flat tan or brown skin markings, commonly referred to as “birth marks”). These must be present on both sides of the body.
  • Freckling in the armpit and groin (easiest to detect in infants or children due to natural skin changes and hair growth in adults that can hide this finding)
  • Two or more “neurofibroma” tumors of any type. This includes skin bumps called cutaneous neurofibromas, deeper “sub-cutaneous” neurofibromas. Alternatively, one single plexiform neurofibroma is sufficient. These are larger tumors that are often very soft and involve the skin and deeper tissues as well.
  • Two or more Lisch nodules (harmless pigmented spots in the colored part of the eye) or two or more abnormalities in the choroid (blood vessel layer detected in the back of the eye by an ophthalmologist)
  • Optic pathway glioma (a tumor of the optic pathway, which includes the optic nerves as well as parts of the brain that carry visual information). They can sometimes be detected by an eye doctor (ophthalmologist), but sometimes they can only be seen on brain imaging.
  • A bony abnormality that is characteristic for NF1, such as malformation of the “sphenoid” bone which is the part of the skull that supports the eyes, or thinning or a gap in the tibia (the shin bone) or other long bones in the arms and legs.
  • Detection of a mutation in the NF1 gene in the blood
  • Having at least one parent who has been diagnosed with NF1 based on the above rules.

Genetic testing is not absolutely necessary for a diagnosis, but it may be recommended if someone has some but not all required features, or in other unique situations that the NF doctor will discuss if they arise.

Treating Neurofibromatosis Type 1  

Although there is no cure for the gene mutation that causes NF1, researchers are racing to develop newer and more effective treatments for the tumors associated with NF1. Koselugo (selumetinib) is the first FDA approved medication to shrink plexiform neurofibromas. NF-associated skin and plexiform neurofibromas should be resected using a technique that will prevent regrowth or spread of the tumors. This should be performed by a dermatologist or surgeon who is an expert in NF and has an understanding of the unique needs of NF patients. The multidisciplinary Neurofibromatosis Clinic at Mount Sinai is comprised of doctors in all fields of specialty who collaborate together to best treat our patients. Additionally, the Neurofibromatosis Clinic at Mount Sinai is dedicated to clinical trials research in NF1 to improve the physical and mental health of our patients.