Neurofibromatosis type 1 (NF1)

Neurofibromatosis type 1 (NF1) is a genetic condition that causes tumours to grow along your nerves. The tumours are usually non-cancerous (benign) but may cause a range of symptoms. There's currently no cure for NF1.

Symptoms of neurofibromatosis type 1

NF1 is a condition you're born with, although some symptoms develop gradually over many years. The severity of the condition can vary considerably from person to person.

In most cases, the skin is affected, causing symptoms such as:

  • pale, coffee-coloured patches (café au lait spots)
  • soft, non-cancerous tumours on or under the skin (neurofibromas)
  • clusters of freckles in unusual places – such as the armpits, groin and under the breast
  • problems with the bones, eyes (reduced eyesight) and nervous system(including migraines and epilepsy)

Certain health problems are often associated with NF1, such as learning difficulties. Less commonly, NF1 is associated with a type of cancer known as malignant peripheral nerve sheath tumours.

Some children with NF1 develop high blood pressure. High blood pressure may be caused by narrowing of the artery to the kidney (renal artery stenosis). This requires specialist treatment if it's found to be causing your child's high blood pressure.

High blood pressure may also be caused by a phaeochromocytoma. This is a tumour of the adrenal glands that is usually benign. It's more common in adults than children.

High blood pressure may be associated with potentially serious complications, such as a stroke or a heart attack, if it's not treated. Children and adults with NF1 should have regular blood pressure checks, usually at least once a year.

Causes of neurofibromatosis type 1

NF1 is caused by a faulty gene. If the NF1 gene is faulty, it leads to uncontrolled growth (tumours) developing in the nervous system.

In half of all cases of NF1, the faulty gene is passed from a parent to their child. Only one parent needs to have the faulty gene for their child to be at risk of developing the condition.

If either the mother or father has the faulty gene, there's a 1 in 2 chance that each child they have will develop NF1.

In other cases, the faulty gene appears to develop spontaneously. It's unclear why this happens. If you have a child who develops NF1 spontaneously, it's highly unlikely any further children you have will also develop the condition.

However, a person who develops NF1 spontaneously can pass the condition to their children.

Diagnosing neurofibromatosis type 1

It's usually easy to diagnose NF1 in adults and older children by checking for the typical symptoms.

It may be diagnosed in babies who show symptoms of NF1 from birth. However, it's not always possible to make a firm diagnosis in early childhood because some symptoms take years to develop.

If NF1 is suspected, further tests such as scans, blood tests or a biopsy may be recommended. This is to assess whether your child has other symptoms or conditions associated with NF1.

If there's uncertainty about the diagnosis, your child may be able to have a blood test to see whether they have the faulty NF1 gene. However, the test is not completely reliable: around 5 per cent of children who test negative for the faulty gene still develop NF1.

Before and during pregnancy

Couples with a family history of NF1 may wish to consider their options before having a baby. Your GP can refer you to a specialist to discuss your options.

These may include:

  • having a child with a donor egg or sperm
  • adopting a child
  • having a test during pregnancy – either chorionic villus sampling or amniocentesis to see if your baby will have NF1
  • pre-implantation genetic diagnosis – where eggs are fertilised in a laboratory and tested to make sure they don't have the NF1 gene, before being implanted into the womb

Treatment for neurofibromatosis type 1

There's currently no cure for NF1. Treatment involves regular monitoring and treating any problems as they occur.

Treatment can involve:

  • surgery – to remove tumours and improve bone abnormalities
  • medication – to control secondary conditions, such as high blood pressure
  • physiotherapy
  • psychological support
  • pain management

Careful monitoring and treatment can help people with NF1 live a full life. However, there's a risk of developing serious problems, such as certain types of cancer that can reduce life expectancy.

NF1 and pregnancy

Most women with NF1 have healthy pregnancies.

However, the number of neurofibromas may increase because of hormone changes. Make sure you're cared for by an obstetrician with knowledge of NF1, or speak to your NF1 specialist.

NF1 and breast cancer

Women under 50 with NF1 have an increased risk of breast cancer and should start having breast screening appointments when they're 40 years old.

The information on this page has been adapted from original content from the NHS website.

For further information see terms and conditions.

This page was published November 2018

This page is due for review October 2021

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