NF Type 1

Neurofibromatosis Type 1 is caused by a mutation in  a gene on chromosome 17.  It affects approximately one in 3,000 people.

Frequently Asked Questions

Neurofibromatosis type 1 (NF1) is a condition characterized by the growth of tumors along nerves in the skin, brain, and other parts of the body. The signs and symptoms of this condition vary widely among affected people.

Neurofibromatosis type 1 occurs in 1 in 3,000 to 4,000 people worldwide.

The symptoms and complications of neurofibromatosis type 1 vary widely from patient to patient. However, beginning in early childhood, most people with neurofibromatosis type 1 have 6 or more café-au-lait spots, which are flat patches on the skin that are darker than the surrounding area. Freckles in the underarms and groin typically develop later in childhood.

Most adults with neurofibromatosis type 1 develop neurofibromas, which are noncancerous (benign) tumors that are usually located on or just under the skin. These tumors may also occur in nerves near the spinal cord or along nerves elsewhere in the body. Rarely, these tumors can progress into a malignant tumor. People with neurofibromatosis type 1 also have a slightly increased chance of developing brain tumors, other cancers and leukemia.

Benign growths called Lisch nodules usually appear in the colored part of the eye (the iris) in the teenage or adult years.. Lisch nodules do not interfere with vision. Some affected individuals also develop tumors that grow along the nerve leading from the eye to the brain (the optic nerve). These tumors, which are called optic gliomas, may lead to reduced vision or total vision loss. In some cases, optic gliomas have no effect on vision.

Additional signs and symptoms of neurofibromatosis type 1 include high blood pressure (hypertension), short stature, an unusually large head (macrocephaly), and skeletal abnormalities such as an abnormal curvature of the spine (scoliosis). Although most people with neurofibromatosis type 1 have normal intelligence, learning disabilities and attention deficit hyperactivity disorder (ADHD) occur frequently in affected individuals.

Again, the complications of NF1 may vary WIDELY from individual to individual. Some people may have a few of the complications, some may have many. It is also a chronic disorder that progresses over time. However, for some it may progress very slowly and others it may be more rapid. It also may progress suddenly or a new complication may appear; or it may suddenly slow down. For instance, a tumor may simply stop growing.

There are different ages in which physicians may especially look for different complications.

NF type 1 is caused by a mutation in a gene on chromosome 17. This gene provides the instructions for making a protein called neurofibromin. This protein is produced in many cells, including nerve cells and specialized cells surrounding nerves (oligodendrocytes and Schwann cells). Neurofibromin acts as a tumor suppressor, which means that it keeps cells from growing and dividing too rapidly or in an uncontrolled way. Specifically, neurofibromin regulates the activity of another protein called RAS, which promotes cell division. When the NF1 gene is mutated, it usually leads to a shortened version of the neurofibromin protein that cannot bind to RAS or regulate its activity. As a result, the RAS protein is more active. Cells are told to begin dividing and never told when to stop, causing the formation of tumors. As a result, tumors such as neurofibromas can form along nerves throughout the body. It’s not yet known how mutations in the NF1 gene lead to the other features of neurofibromatosis type 1, such as café-au-lait spots and learning disabilities.

Read more about the NF1 gene.

Scientists are still trying to discover why the symptoms vary so much, even among people from the same family. One theory is that each patient’s unique genetic makeup influences the severity of his or her symptoms; meaning that genes other than the NF1 gene might play a role. Scientists call these “modifier genes,” and they could be any of the thousands of genes in the human genome.

How do modifier genes work? Proteins encoded by modifier genes might work in the same biological pathways as neurofibromin, and therefore affect how well these pathways work. Variations in the DNA sequence of a modifier gene may alter its function enough to influence the severity of NF1 in an individual.

To date, scientists have not found any strong candidate NF1 modifier genes.

It’s also possible that environmental events may cause the variability among different NF patients. Also, the different types of mutations that occur in the NF1 gene may be a factor. Currently, over 500 different types of mutations have been discovered in the NF1 gene.

Approximately half (50%) of all people with neurofibromatosis type 1 inherit the disorder. It is inherited in an autosomal dominant pattern, which means that only one copy of the defective gene has to be inherited for a baby to be born with NF1. Therefore, each child of a parent with NF1 runs a 50 percent risk of getting the disorder.

In the other half of NF1 cases, a person will have no family history of the disease. The mutation is new and has likely occurred early in life (during the development of the embryo). New mutations are frequently the cause of NF1 because the NF1 gene is very large, making it more likely to have a mutation.

Most of the time, NF1 is diagnosed by its physical symptoms (tumors or café- au-lait spots), or by a family history of the disorder. The café- au-lait spots usually appear within the first two years of a child’s life. A person may be diagnosed with NF1 if they have at least two of the following features:

  1. Six or more café-au-lait spots (brown oval or circular spots on the skin)
  2. Two or more benign skin tumors called neurofibromas, or one diffuse tumor of the soft tissue or nerves called plexiform neurofibroma
  3. Freckles under the arm or in the groin region
  4. A tumor of the nerve to the eye called an optic glioma
  5. Two or more spots on the iris called Lisch nodules
  6. A problem of one of the bones such as bowing of a leg with or without a fracture
  7. A parent, brother, sister, or child with NF1

NF1 may also be diagnosed by sequencing a person’s NF1 gene to identify mutations. But because of the gene’s large size and the high number of possible mutations that can occur, genetic testing is usually not practical – and very expensive.

Doctors may not recommend genetic testing because a diagnosis of NF1 is fairly easy to confirm on the basis of its physical signs, and currently genetic testing offers no extra benefits for treatment. This is something that may be changing.

It is, however, easier to identify a mutation if there is a family history of NF1. If another family member has been tested, and the mutation has been identified, then it becomes relatively easy to look for that same mutation in other family members. Finding the mutation would then confirm the diagnosis of NF1.

There is no cure or treatment for NF1. Some tumors may be removed, but others, such as plexiforms may be difficult to manage and may only be “debulked”. Optic gliomas may be treated with chemotherapy, though it is only warranted if they progress and cause complications such as vision changes. Bony abnormalities may be treated surgically or through instrumentation.

It is EXTREMELY CRITICAL that people with NF1 are treated by physicians that have a lot of experience in the disorder, especially if there are ANY complications. If you cannot get to an “NF Specialist”, please contact us for other options.

  • Neurofibromatosis 1
  • NF1
  • Peripheral Neurofibromatosis
  • Recklinghausen Disease, Nerve
  • von Recklinghausen Disease

References (14 links)

NF1 Resources and iNFo

Overall Care

Information for Medical Professionals
created by NF Midwest (be iNFormed Series)

Neurofibromatosis Type 1 Revisited
from Pediatrics, Official Journal of the American Academy of Pediatrics 2009

Clinical Manifestations and Management of Neurofibomatosis Type 1
by James Tonsgard, MD 2006

Primary Care for Patients with Neurofibromatosis Type 1
by Leigh Hart, RN, CCRN, PhD, in Nurse Practitioner 2005

Possible Complications of NF1 Shown on BodySheet

Vascular Disease in Neurofibromatosis-1
Cynthia Hingtgen, MD, PhD (be iNFormed Series)

Neurofibromatosis Type 1 and Aging (webinar)
presented by NF Network

Volumetric Measurement in Neurofibromatosis
by Diana Haberkamp, reviewed by Eva Dombi,  MD


Optic Gliomas
by Robert Listernick, MD 2012 (be iNFormed Series)

Optic Gliomas (webinar)
from Pediatrics, Official Journal of the American Academy of Pediatrics 2009

Neurofibromas (What They are and Types of)
by James Tonsgard, MD 2015 (be iNFormed Series)

Insurance Coverage of Fibroma Removal
by NF Midwest (be iNFormed Series)

Procedure Codes for Removing a High Quantity of Neurofibromas
by NF Midwest (be iNFormed Series)

Tumor Suppressor Research
from the CDMRP 2013


Socialization Issues in NF1
presentation by Dr. Scott Hunter (University of Chicago) at an NF Midwest Symposium in October 2013

Social Emotional Development in Children with NF (webinar)
presented by NF Network with Sandy Cushner-Weinstein, PT, LCSW-C


Executive Functioning and NF1
as presented by Tiffany Dell’Aquila, PSY.D, NF Midwest Symposium 2015

Learning in Neurofibromatosis Type 1 
by Drs. Scott Hunter and James Tonsgard, University of Chicago 2012 (be iNFormed Series)

Comprehensive Neuropsychological Evaluations for Children with NF1
by Jill Isenberg, Ph.D., ABPP; St. Louis Children’s Hospital 2012 (be iNFormed Series)

A Neuropsychological Perspective on Attention Problems in Neurofibromatosis Type 1
by Alexandra K. Templer, Jeffrey B. Titus and David H. Gutmann 2012

Neurofibromatosis Type 1 Information for Teachers
by NF Midwest (be iNFormed Series)

NF and School Issues (webinar) 
presented by NF Network

Early Signs of Learning and Attention Vulnerability in NF1 (webinar)
presented by NF Mid-Atlantic

Neuropsychological Functioning in Neurofibromatosis (webinar)
presented by NF Mid-Atlantic

National Center for Learning Disabilities

Learning Disabilities Association of America

LD Online 
The educators’ guide to learning disabilities and ADHD

Brain training exercises

Handwriting Without Tears
Our easy-to-teach, easy-to-learn curriculum makes handwriting mastery joyful for students and their teacher

101 Noteworthy Sites on Asperger’s and the Autism Spectrum


Helping your Child Cope with Neurofibromatosis
from presentation by Helen Hand, PhD 1998 PDF

How Parents Can Help Their Child Cope with a Chronic Illness
from the Center for Effective Parenting

How Do I Talk About NF1
from the University of Alabama

Social Emotional Development in Children with NF (webinar)
Sandy Cushner-Weinstein, PT, LCSW-C (Children’s National Medical Center & Camp New Friends) from the NF Network in September 2014

Talking with Children about Neurofibromatosis
from the Neuro Foundation, London

Health Supervision for Children With Neurofibromatosis Type 1
by Joseph H. Hersh, MD, and the Committee on Genetics (Mar 2008)

Anti-Bullying Webinar
by the NF Network March 6, 2013

Transitioning to Adult Care
Presentation by Dr. Parag Shah (Lurie Children’s Hospital) t an NF Midwest Symposium in October 2014

Women Issues and Family Planning

Reproductive Options for People with NF1, NF2 and Schwannomatosis
by Amanda Bergner, MS CGC, Johns Hopkins University


Understanding Seizures in NF1 (webinar) 
with Dr. James Tonsgard (University of Chicago) provided by the NF Network from May 2014



Pain in Neurofibromatosis Type 1
by Staci Martin Peron, PhD and Andrea Baldwin, CRNP from the National Cancer Institute, National Institutes of Health (be iNFormed Series)


Managing Pain in Neurofibromatosis (webinar)
presented by NF Mid-Atlantic 2013 with Andrew Tyler Putnam, MD


Whole Gene Deletion in NF1
by Heather Radtke, MS, CGC, Children’s Hospital of Wisconsin (be iNFormed Series)

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