Neurofibromatosis is a genetic disease that causes tumours to form on nerve tissue. These tumours can develop anywhere in the nervous system, including the brain, spinal cord, and nerves. The tumours in these disorders are usually non-cancerous (benign), but sometimes they can become cancerous (malignant). The symptoms are often mild. However, complications of neurofibromatosis can include hearing loss, learning impairment, cardiovascular problems, loss of vision, and severe pain.  

There are three types of neurofibromatosis that are each associated with unique signs and symptoms, with neurofibromatosis type 1 being the most common.

Neurofibromatosis type 1 (NF1) is a disorder where signs are often noticeable at birth or shortly afterward and almost always by age 10. The worldwide incidence of NF1 is 1 in 2,500 to 1 in 3,000 individuals.

Signs and symptoms are often mild to moderate but can vary in severity, and include:

Café-au-lait spots. These are flat, light brown spots on the skin, which are harmless and common in many people. Having more than six café-au-lait spots suggests NF1. They are usually present at birth or appear during the first years of life. After childhood, new spots stop appearing.

Freckling in the armpits or groin area. Freckling usually appears at ages 3 to 5. Freckles are smaller than cafe au lait spots and tend to occur in clusters in skin folds.

Lisch nodules. These are tiny bumps on the iris of the eye (melanocytic iris hamartomas). These harmless nodules cannot easily be seen and do not affect vision.

Neurofibromas. These are soft, pea-sized bumps on or under the skin. They are benign tumours that usually develop in or under the skin but can also grow inside the body. Sometimes, a growth will involve many nerves (plexiform neurofibroma). Plexiform neurofibromas, when located on the face, can cause disfigurement. Neurofibromas may increase in number with age.

Optic glioma. These tumours on the optic nerve usually appear by age 3, rarely in late childhood and adolescence, and almost never in adults.

Bone deformities. Abnormal bone development and a deficiency in bone mineral density can cause bone deformities such as a curved spine (scoliosis) or a bowed lower leg.

Macrocephaly and short stature. Children with NF1 tend to have a larger than average head size due to increased brain volume, and they often are below average in height.

Learning disabilities. Impaired thinking skills are common in children who have NF1 but are usually mild. Often, there is a specific learning disability, such as a problem with reading or mathematics. Attention-deficit/hyperactivity disorder (ADHD) and speech delay are also common.

NF1 has been associated with other tumours of the central nervous system, which include astrocytomas of the visual pathways, ependymomas, meningiomas, and some primitive neuroectodermal tumours. Individuals with the disorder have an increased susceptibility to the development of rare cancerous (malignant) tumours as well. Involvement of the heart and blood vessels in neurofibromatosis has been described, particularly renal artery stenosis due to ‘vascular neurofibromatosis’, which is a relatively common cause of hypertension in patients with NF1.

NF1 is caused by a harmful change (pathogenic variant) in one copy of the NF1 gene (neurofibromin gene) that either is passed on by a parent or occurs spontaneously at conception.

Neurofibromatosis treatment usually focuses on encouraging healthy growth and development in children who are affected by the disorder and on early management of complications. When neurofibromatosis causes large tumours or tumours that press on a nerve, surgery can reduce symptoms. Some people may benefit from other therapies, such as stereotactic radiosurgery or medications to control pain.

We are here for you.

Dr. Chayim Schell-Apacik is a specialist in clinical genetics with over three decades of experience in supporting patients. We offer individualised evaluations, genetic consultation, and testing, with the goal of providing you with genetic information that presents choices and minimises uncertainty, empowering you to make decisions that are most beneficial for you. Please contact us, to find out more.

What is genetic testing?

Genetic testing – sometimes called genomic testing, finds changes in the genetic material that can cause health problems. It is mainly used to diagnose rare and inherited health conditions and some cancers.
You may be offered a genetic test because your doctor thinks

• you or your child might have a health condition caused by a change in the genetic material involving one or more genes or certain chromosomes.
• someone in your family has a health condition that is caused by changes in the genetic material involving one or more genes, or certain chromosomes.
• some of your close relatives have had a particular type of cancer that could be inherited.

At Schell Genetics, we are here to assist you in this process. Please don’t hesitate to contact us.

Learn more about other RARE DISEASES or GENETIC DISORDERS