Tuberous sclerosis, also known as tuberous sclerosis complex, is a rare genetic condition that causes mainly non-cancerous (benign) tumours to develop in different parts of the body.

The tumours most often affect the brain, skin, kidneys, heart, eyes and lungs.

Tuberous sclerosis is present from birth, although it may not cause obvious problems immediately.

What problems can tuberous sclerosis cause?

The tumours caused by tuberous sclerosis can result in a range of associated health problems, including:

• epilepsy – a condition that causes seizures (fits)
• learning disabilities
• hyperactivity
• an autistic spectrum disorder
• skin abnormalities – such as patches of light-coloured or thickened skin, or red acne-like spots on the face
• the kidneys not working properly
• breathing difficulties
• a build-up of fluid on the brain (hydrocephalus)

These problems can range from mild to severe, and it's possible to have only a few of these problems or a wide range. Members of the same family may be affected very differently by tuberous sclerosis.

What causes tuberous sclerosis?

Tuberous sclerosis is caused by mutations (changes) in either the TSC1 or TSC2 gene. These genes are involved in regulating cell growth, and the mutations lead to uncontrolled growth and multiple tumours throughout the body.

In around 3 in every 4 cases, the genetic fault occurs for no apparent reason in people without any other affected family members.

In the remaining 1 in 4 cases, the fault is passed on to a child by their parents. Only 1 parent needs to carry the faulty gene to pass it on, and a parent who has 1 of the faulty genes has a 1 in 2 chance of passing it on to each child they have.

The parent carrying the faulty gene will also have tuberous sclerosis, although sometimes it may be so mild that they do not realise.

How tuberous sclerosis is treated

There is no cure for tuberous sclerosis, but there is a range of treatments for many of problems caused by the condition.

For example:

• epilepsy may be controlled with medicine or, in some cases, surgery
• extra educational support can help children with learning disabilities
• challenging behaviour and psychiatric problems - such as autism, anxiety or depression - can be treated with behavioural interventions and medicine
• brain tumours can be surgically removed or shrunk with medicine
• the facial rash can be treated with laser therapy or medication applied to the skin
• medicine can control symptoms caused by reduced kidney function and can help to shrink kidney tumours
• lung problems can be treated with medication

Research has found that in a type of medicine known as an mTOR inhibitor, which interrupts the chemical reactions needed for tumours to grow, may be a useful treatment in the future.

People with tuberous sclerosis will also need to have regular tests to monitor the function of the organs that can be affected by the condition.

Outlook

The outlook for people with tuberous sclerosis can vary considerably.

Some people have few symptoms and the condition has little impact on their life, while others – particularly those with a faulty TSC2 gene or obvious problems from an early age – can have severe and potentially life-threatening problems that require lifelong care.

Many people will have a normal lifespan, although a number of life-threatening complications can develop. These include a loss of kidney function, a serious lung infection called bronchopneumonia and a severe type of epileptic seizure called status epilepticus.

People with tuberous sclerosis may also be at an increased risk of developing certain types of cancer, such as kidney cancer, but this is rare.

Tuberous Sclerosis Association (TSA)

The TSA provides information, advice and support to individuals and families affected by tuberous sclerosis.

You can visit the TSA website for more information and to access their online community. You can also contact the organisation's specialist advisers in your area.

Tuberous sclerosis is a lifelong condition that requires long-term care and support from a range of different healthcare professionals.

If your child is affected, an individual care plan will be drawn up to address any needs or problems they have. As your child gets older, the plan will be reassessed to accommodate changes to their needs or situation.

Their care plan is likely to include details about any treatment or support they need, as well as the routine tests that will be necessary to monitor their condition.

Read on to learn about how tuberous sclerosis is monitored and some of the treatments available.

Monitoring the condition

Regular testing is important for people with tuberous sclerosis. This is so the function of the organs often affected by the condition – such as the brain, kidneys and lungs – can be regularly monitored and assessed.

Tests and checks that may be recommended include:

• MRI scans - to check for changes in tumours in the brain or kidneys
• ultrasound scans - to check for heart and kidney tumours
• blood tests - to check how well the kidneys are working and other things, such as vitamin D levels
• electrocardiograms (ECGs) - to detect abnormal electrical activity in the heart
• CT scans - to check the function of the lungs, such as measuring how much air a person can breathe out
• skin and eye examinations - to look for any changes
• blood pressure measurements
• questions about your child’s behaviour and development

How often these tests are needed will depend on your or your child's age and the symptoms you or they have. Some are carried out annually, while others are done once every few years.

Epilepsy

Epilepsy is a very common feature of tuberous sclerosis and can sometimes be difficult to control.

Medicines to control the seizures (anti-epileptic drugs) will usually be tried first, although they're not always effective for people with tuberous sclerosis.

If the first medicine is not effective, the dose can be increased. You can also try a different medicine, or you may be prescribed 2 medicines to take at once.

If medication doesn't control the seizures, one of the following procedures may be recommended:

• surgery to remove any tumours in your brain that may be causing the seizures
• vagus nerve stimulation (VNS) – where a small electrical device is implanted under the skin to send pulses of electricity to the brain
• a special diet - the ketogenic diet or a modified version of it

Behavioural and learning problems 

If your child is experiencing behavioural problems or has a learning disability, they may be referred to a psychologist for an assessment.

A special educational needs plan may be drawn up to outline any extra educational support your child may require.

For some children, it may be possible for extra support to be given at a mainstream school, while others may benefit from attending a special school.

Brain tumours

Any brain tumours will be detected and monitored closely so treatment can be carried out if necessary.

A brain tumour may need to be surgically removed if there's a risk it could get too big and cause a build-up of fluid on the brain (hydrocephalus).

Research has also found that a medication called everolimus shrinks most brain tumours, preventing them from causing hydrocephalus and potentially improving epilepsy as well.

Everolimus is a type of mTOR inhibitor, which interrupts or blocks the chemical reactions needed for tumours to grow. They are a useful treatment for some of the problems caused by tuberous sclerosis.

Long-term studies carried out over several years have shown them to be very effective and longer-term studies are under way.

Skin problems

Abnormal growths or patches of skin don't usually present a serious health problem, but their appearance can affect a person's confidence and self-esteem.

Laser therapy can be used to improve the appearance of the skin if necessary. If the growths or patches return, repeated laser therapy may be required. Using sun cream is also important to protect the skin.

Research has shown the effectiveness of mTOR inhibitor cream in treating skin abnormalities caused by tuberous sclerosis. The rash also usually shows significant improvement in those taking mTOR inhibitors as tablets for their kidneys or brain tumours.

Kidney tumours

Treatment for kidney tumours and growths will depend on the problems they cause.

For example, if kidney tumours cause high blood pressure (hypertension), medicine can be used to help lower it. Read more about treating high blood pressure.

Everolimus may be used to stop tumours becoming too large, as large tumours can cause dangerous bleeding. However, as this is a relatively new treatment, the long-term effects are not yet fully known.

If a tumour bleeds, a procedure called embolisation may be recommended. A special substance is injected into the tumour to block its blood supply, which starves it of oxygen and nutrients, causing it to shrink.

Very rarely, if you have a severe or total loss of kidney function, you may require dialysis or a kidney transplant.

Heart tumours

In most cases, heart tumours will not need treatment. Heart tumours in babies usually shrink as the child gets older, until they are barely detectable as adults.

However, in some rare cases, surgery may be required to remove the tumours if they begin to seriously affect the functioning of the heart.

Sometimes, the heart tumours affect the electrical conduction on the heart and cause abnormal heart rhythms. These problems occasionally need treatment with medication.

Lung tumours

Women with lung tumours may require medicine to shrink the tumours.

Research has shown that a mTOR inhibitor called sirolimus is effective, although it can cause side effects such as feeling sick and constipation or diarrhoea. It’s available to treat lung tumours caused by tuberous sclerosis through the National Centre for Lymphangioleiomyomatosis (LAM) at the University Hospital of Nottingham.

If lung tumours lead to a collapsed lung, emergency surgery is required to repair the lung and drain any air that has escaped into the chest.

In very severe cases, a lung transplant may be required.

Eye tumours

Eye tumours rarely need any treatment, because they don't usually grow big enough to impair vision. In rare cases, where vision is affected, a technique called photocoagulation can be used.

Photocoagulation is a type of surgery that uses lasers to burn away the blood vessels supplying the eye tumours with blood. Blocking the blood supply should shrink the tumours.