Neurofibromatosis type 1 (NF1) is a very common genetic condition. Approximately 1 in every 2,500 people is born with NF1. NF1 varies widely in how if affects those who have the condition. Many people with the disorder will be affected very mildly and may have nothing more than skin changes. A minority of people (around a third) who have NF1 will have medical problems related to the disorder at some time in their life. Some of these problems will be mild and easily treatable and others will be more severe.


Diagnosis is made if an individual has two or more of the following features:

  • Six or more café au lait (coffee coloured patches) which are the size of a pencil top or bigger. These usually appear during the first year of life and can increase in size and number. Café-au-lait patches are generally harmless and there is no connection between the number or size of café-au-lait patches and the severity of the condition. They sometimes fade later in life.
  • Neurofibromas (small benign pea-sized growths or lumps) on or under the skin. These are a common feature of NF1. They usually appear during adolescence and tend to increase in number throughout life
  • Freckling under the arm or in the groin area
  • Plexiform Neurofibromas – large bundle of nerves are thickened and appear as a soft tissue mass under the skin. These growths are often large, and can first appear as swelling.
  • Optic Glioma: thickening of the optic nerve
  • Lisch nodules – these are small pigmented areas in the iris (coloured part) of the eye
  • Another close family member has NF1.

Should you think that you or a family member has NF ask your GP to refer you to our clinic where we can assess you.

How does NF1 affect the body

If someone has NF1, he or she will have it for life. There is as yet no specific medical treatment or gene therapy to cure, prevent or reverse the condition.

Many people who have been diagnosed with NF1 never experience health problems. However, some people who have NF1 can develop some of the complications that are known to happen in this condition. The development of some of these features is related to age and some complications can first appear in childhood. Specific complications can be treated medically or surgically depending on the problem

NF1 is a complex disorder and one of its features is how variable the condition is from one person to another, even within members of the same family. At present there is no way to predict how mildly or severely any individual will be affected; however, specific complications of NF1 respond best to early treatment. Below are thespecific complications that can occur with NF1.

Ophthalmic (Eyes)

NF1 can cause problems at the back of the eye in the form of an optic nerve tumour/swelling called an optic glioma, which is most likely to occur in early childhood, up to about the age of seven.

An optic glioma is a non-cancerous growth that involves the cells of the optic nerve. Sometimes there can be vision problems or occasionally it can cause early puberty in a very small percentage of cases. Where this complication is diagnosed during childhood, it rarely progresses in adulthood, but it needs careful monitoring by an ophthalmologist.

Dermatological (Skin)

Neurofibromas are benign tumours / growths that develop on or under the skin or along a nerve. They can occur anywhere on the body where there are nerves. They may look and feel like small pea-sized lumps on or under the skin. Neurofibromas that grow on the skin are usually soft and painless. Those that are under the skin are usually firmer to touch but are usually also painless. Other neurofibromas may be deep in the body and cannot be felt from the outside.

These nodules usually develop over time and can continue to grow in size. Typically, adults with NF1 will acquire more neurofibromas as they age because they do not go away. There is no way to predict how many neurofibromas a person with NF1 will develop or when or where on the body they will develop. This feature of NF1 varies greatly from person to person. There is nothing a person can do to prevent or slow the growth of neurofibromas. Although many people with NF1 tend to tan easily without sunburn it is important to use a high factor sun block and sun protection, as prolonged exposure to the sun may increase neurofibromas in later life.

Hypertension (high blood pressure)

Occasionally NFI can cause high blood pressure. It is recommended that everyone with NF1 should have his or her blood pressure checked once a year throughout life. Sometimes high blood pressure may not be related to NF1 and it is a common and treatable condition in adults who do not have NF1.


Lateral curvature of the spine, known as scoliosis, is common in NF1. In most cases it is mild. Scoliosis usually appears in early childhood. A child with scoliosis will need periodic spine X-rays and physical examinations to determine whether corrective measures are needed. In some cases, a brace may be used to prevent progression of the problem. More serious cases may require corrective surgery.

Orthopaedic (Bones)

The variety of bone defects seen in NF1 are usually evident at birth. Most are uncommon. Defects can occur in almost any bone, but are seen most often in the skull and limbs. They include:

Congenital absence of the orbital wall, the bone normally surrounding the eye. Its absence may cause slight bulging of the skin around the eye.

Bowing of the leg bones below the knee (tibia or fibula). These bones may be thinner than normal and bowed. If a fracture occurs, healing may be slow or incomplete. Incomplete healing, called pseudarthrosis, may also affect the bones in the forearm (radius or ulna), but this occurs very rarely. This is a difficult problem, which requires the supervision of an orthopedic surgeon.

Plexiform neurofibromas

Some neurofibromas can grow in a wide, spreading fashion around large nerves and may feel like a bunch of knots or cords beneath the skin. These types of growths are called plexiforms. Sometimes they will be obvious in early life as an area of swelling but other times they can lie deeper in the body and are harder to detect. They can grow anywhere on the body and, occasionally on the face.

Learning Difficulties

Although intelligence (IQ) studies have shown that the vast majority of people who have NF1 are within the normal intelligence range, somewhere between a third and two thirds of people who have the condition will experience some problems with learning. It is the most common complication of NF1. However, it is important for parents to note that the majority of children who have NF1 are educated in mainstream schools and do not require special education.

Children and adults who have NF1 and who have learning problems may find difficulty reading and writing, they may find it hard to concentrate, have memory difficulties or have poor coordination. Where someone with NF1 has learning problems, this is often evident from their earliest years at school and, as children, they often underachieve at school and may have difficulties establishing and maintaining peer friendships. They can appear socially immature, have difficulties with concentration and sometimes be clumsy and uncoordinated.

It is important that these problems are recognised as early as possible so that teachers are aware of how NF1 can affect school performance. It is useful to have a frank discussion with the teacher so that common misconceptions about NF1 can be dispelled and the child can get help in school if he or she needs it. Learning and behaviour problems in NF1 are not progressive, that is: they do not get worse over time. In fact, they can usually be improved with appropriate help.