The symptoms of neurofibromatosis type 1 (NF1) are often mild and cause no serious health problems. But some people will have severe symptoms.

The symptoms of NF1 can affect many different areas of the body, but it's unlikely someone will develop all of them.

The skin

Coffee-coloured patches

The most common symptom of NF1 is the appearance of painless, coffee-coloured patches on the skin, called café au lait spots. However, not everyone with café au lait spots has NF1.

The spots can be present at birth or develop by the time a child is 3 years old.

During childhood, most children with NF1 will have at least 6 café au lait spots around 5mm across. These grow to about 15mm during adulthood.

The number of spots someone has is not related to the severity of the condition. For example, a person with 10 spots has the same chance of developing further problems as someone with 100 spots.

Freckles

Another common symptom of NF1 is clusters of freckles in unusual places, such as the armpits, groin and under the breast.

Tumours on or under the skin

As a child gets older, usually during teenage years or early adulthood, they develop tumours on or under their skin (neurofibromas).

These are caused by non-cancerous tumours that develop on the coverings of nerves. They may vary in size, from pea-sized to slightly bigger tumours. Some neurofibromas are purple.

The number of neurofibromas can vary. Some people only have a few, while others have them on large sections of their body.

Most neurofibromas are not particularly painful, but they may be visible, catch on clothes and occasionally cause irritation and stinging.

However, if neurofibromas develop where multiple branches of nerves come together (plexiform neurofibromas), they can cause large swellings.

Plexiform neurofibromas sometimes occur on the skin but may also develop on larger nerves deeper in the body. They may sometimes cause symptoms including pain, weakness, numbness, bleeding, or bladder or bowel changes.

Learning and behaviour

Some children with NF1 develop learning and behavioural problems. It's unclear why this happens.

Children with NF1 who have a learning difficulty may have normal or slightly lower-than-average intelligence, but they can usually be taught at a mainstream school.

Attention deficit hyperactivity disorder (ADHD) affects around half of all children with NF1 and causes problems with attention span, concentration and controlling impulses.

NF1 has also been linked with autism spectrum disorder (ASD), and some children may have difficulty in social communication.

The eyes

Around 15% of children with NF1 develop a tumour on their optic pathway.

The optic pathway is located at the back of each eye and sends information from the eyes to the brain. This type of tumour is known as an optic pathway glioma (OPG).

Children under 7 years of age are known to have the highest risk of developing this type of tumour. These tumours are often small, grow slowly and do not cause any noticeable symptoms.

Children with faster-growing OPGs may have problems with their vision, including:

• objects becoming blurry
• changes in how they see colours
• a reduced field of vision
• squinting
• one eye looking more prominent than the other

Younger children may be unable to explain that they have vision problems. You should be aware of any signs that your child has difficulty seeing, such as problems picking up small objects or bumping into things.

The best way of detecting these tumours is to have eye tests a minimum of once a year until your child is at least 7 years old.

Another common feature of NF1 is the appearance of tiny, raised brown spots in the coloured central part of the eye (iris). These are known as Lisch nodules and do not usually cause any noticeable symptoms or vision problems.

High blood pressure

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.

Physical development

Many children with NF1 have one or more problems affecting their physical development, including:

• a curved spine (scoliosis) – thought to affect around 10% of children with NF1
• a larger-than-average head – this occurs in around half of all children
• smaller size and lower weight than normal – this is common in many people with NF1

Around 2% of children with NF1 develop pseudarthrosis. This is when abnormal bone development causes curving (bowing) of the limb, usually in the tibia bone of the lower leg. The bone may fracture after a minor injury. The fracture does not heal completely, which affects the normal movement of the leg.

The brain and nervous system

Symptoms affecting the brain and nervous system are relatively common in NF1.

Many people with NF1 get migraines.

Some people develop brain tumours, although this is rare. The tumours may cause no noticeable symptoms. However, tumours in certain parts of the brain occasionally cause symptoms, such as:

• personality changes
• weakness on one side of the body
• difficulties with balance and co-ordination

Some children with NF1 develop epilepsy, where a person has repeated seizures or fits. This tends to be a mild form of epilepsy that's usually controlled easily with medication.

Malignant peripheral nerve sheath tumour

One of the most serious problems that can affect a person with NF1 is a malignant peripheral nerve sheath tumour (MPNST).

MPNSTs are a type of cancer that develops within a plexiform neurofibroma. It's estimated that people with NF1 have around a 15% chance over their lifetime of developing a MPNST.

Most cases first develop when people are in their late 20s or early 30s, but they can occur at any age.

Symptoms of an MPNST include:

• the texture of an existing neurofibroma changing from soft to hard
• an existing neurofibroma suddenly growing much larger
• persistent pain lasting for more than a month or waking you up at night
• suddenly having problems with your nervous system that you did not have before, such as weakness, numbness or tingling in your arms and legs
• loss of bladder or bowel control
• difficulty breathing or swallowing

If you have any of these symptoms, contact the doctor in charge of your care as soon as possible.

Gastrointestinal tumour

Some people with NF1 can develop a gastrointestinal tumour (GIST), which may cause symptoms such as:

• abdominal pain
• changes in bowel habits – such as diarrhoea or constipation
• bleeding from the bottom

Gastrointestinal tumours require management at a specialist centre.

Specialist centres

If you need specialist management, you should be referred to a specialist centre with experience in diagnosing and treating MPNST.

There are currently two centres, one in Guy's & St Thomas' NHS Foundation Trust in London and the other in the Central Manchester University Hospitals NHS Foundation Trust.

Treatment for neurofibromatosis type 1 (NF1) involves regular monitoring and may include physiotherapy, psychological support and pain management. Any problems are treated by a team of health professionals.

If you develop complex problems, you'll usually be referred to one of two specialist NHS centres so a treatment plan can be drawn up. These are:

• Guy's & St Thomas' NHS Foundation Trust in London
• Central Manchester University Hospitals NHS Foundation Trust

Monitoring

Most children with NF1 are advised to have a comprehensive examination each year. This may include:

• a detailed skin examination to check for new plexiform neurofibromas – older children may also be monitored for neurofibromas
• a vision test and an examination of both eyes
• a bone assessment to check for problems such as curvature of the spine (scoliosis) or poorly healed bone fractures
• behavioural assessments
• blood pressure measurement
• measuring their physical development
• assessing their progress at school – abilities in activities such as reading, writing, problem solving and comprehension

As a child gets older, they should ideally still be seen once a year. Over time, they'll learn to monitor their own health so they know when to seek help. However, they may need more assessments if they develop complex health needs.

Contact your specialist centre if your child develops any new symptoms in between their annual examinations or if their existing symptoms get worse.

Adults with NF1 also need regular assessments. These may include:

• detailed skin examination to check for neurofibromas
• a bone assessment to check for problems such as curvature of the spine (scoliosis) or vitamin D deficiency
• blood pressure measurement
• neurological assessment
• assessing emotional wellbeing and how their employment is going
• assessing any learning problems – some adults may benefit from adult literacy classes

Skin problems

Café au lait spots

There's usually no need for treatment of café au lait spots, which are common in NF1. Sometimes they fade as people get older.

If your child finds these patches particularly distressing, one option is to use make-up to cover them up. Camouflage make-up specially designed for covering up skin blemishes is available over the counter at pharmacies.

Neurofibromas

The tumours on or under the skin (neurofibromas) may not require any treatment if they're small. However, treatment can be used if the neurofibromas are painful or causing emotional distress.

Plastic surgery is usually needed. The surgeon cuts the neurofibromas out of the body before resealing the skin.

Depending on the size and location of the neurofibromas, they may be able to be treated with laser surgery or an electric current (electrodessication) instead.

The results of surgery are usually good, although the procedure can leave some thickened scarring and there may occasionally be a delay in wound healing.

Plexiform neurofibromas

Surgery for plexiform neurofibromas (painful neurofibromas that develop inside branches of nerves) can be more challenging. This is because these types of tumours often spread into nearby tissue and may press on important bone structures.

Damage to the nerves can sometimes occur after surgery. This can lead to complications such as a loss of sensation or an inability to move a part of the body.

You should consult a specialist neurofibromatosis centre for advice about removal of plexiform neurofibromas and other treatments that may be available.

Learning difficulties

If your child has a learning difficulty, support is available.

Contact the special educational needs co-ordinator (SENCO) in your child's school or nursery.

Contact your local council if your child isn't in a school or nursery.

As well as extra help in class, some children with NF1 require additional support from other professionals, such as:

• a speech and language therapist
• an educational psychologist, who helps improve learning abilities
• an occupational therapist, who helps improve the skills needed to carry out daily activities

Read more about support for children with special educational needs and disabilities.

High blood pressure

Some people can control high blood pressure by making lifestyle changes including:

• reducing the amount of salt in their diet
• doing regular exercise
• maintaining a healthy weight
• moderating alcohol consumption and not smoking (in adults)

Very high blood pressure requires treatment with medication.

Read more about treating high blood pressure.

Optic pathway tumours

If your child develops a tumour inside the nerve connecting the eye and the brain (the optic nerve) that does not cause any symptoms, no immediate treatment is necessary. This type of tumour, called an optic pathway glioma (OPG), is usually very small and slow-growing.

However, if your child has an OPG, they will need regular eye examinations to monitor the tumour. If your child experiences symptoms, chemotherapy can be used to help shrink the tumour.

Radiotherapy is not used for optic nerve tumours because it can cause problems with cancerous tumours, blood vessels, hormones and learning.

Bone problems

Scoliosis

Treatment for an abnormally curved spine (scoliosis) depends on how severe the curvature is.

Mild cases do not always require treatment because your child's spine may correct itself as they get older. Moderate cases can be treated using a back brace.

Surgery may be required to realign the bones of the spine into the correct position in severe cases of scoliosis.

Read more about treating scoliosis.

Pseudarthrosis

Surgery can also be used to treat poorly healed bone fractures that disrupt the normal movement of the bones (pseudarthrosis).

Possible surgical options are to reconnect two pieces of bone using metal screws and rods or to carry out a bone graft.

A bone graft is where a fracture in the bone is repaired by taking a small section of bone from another part of the body and using it to "plug" the fracture. The grafted section of bone will grow into the surrounding bones.

In a small number of cases involving the bones of the limbs, surgery does not repair the bone. In this case, it's necessary to amputate a section of the limb in order to restore normal function.

People with pseudarthrosis should always be referred to specialist orthopaedic centres used to treat this complication.

Brain and nervous system problems

Tumours

Tumours developing inside the brain or nervous system do not always cause symptoms, but they can disrupt the normal functions of the body.

If treatment is needed, it may involve surgery or drug treatment.

Radiotherapy for tumours

Radiotherapy should not be used to treat benign tumours as it can increase the risk of developing cancer.

It's sometimes used to treat malignant tumours on the advice of specialist doctors.

Epilepsy

Epilepsy can be treated with a number of different medications that help reduce the frequency of seizures. Read more about treating epilepsy.

Malignant peripheral nerve sheath tumour

If you develop cancer in a neurofibroma on the nerve covering, called a malignant peripheral nerve sheath tumour (MPNST), surgical removal is usually recommended.

Radiotherapy and chemotherapy may be given after surgery to reduce the risk of the cancer coming back, although it's uncertain how effective these additional treatments are.

Glomus tumours

Glomus tumours are benign tumours that form around the nail bed in the fingers or toes. Sometimes they lead to purple discolouration around the nail bed.

People with glomus tumours may experience severe pain in a finger after knocking it, when there is change in temperature or if they press on the nail bed.

Glomus tumours are sometimes diagnosed with an MRI or ultrasound scan. They can be removed surgically, which this cures the symptoms.