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. It's estimated that around 1 in every 6,000 babies are born with the condition.
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
- behavioural problems – such as hyperactivity or 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 of problems. Members of the same family may be affected very differently by tuberous sclerosis.
Read more about the features of tuberous sclerosis and diagnosing 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 three in every four cases, the genetic fault occurs for no apparent reason in people without any other affected family members.
In the remaining one in four cases, the fault is passed on to a child by their parents. Only one parent needs to carry the faulty gene to pass it on, and a parent who has one of the faulty genes has a one in two 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 don't realise it.
How tuberous sclerosis is treated
There is currently no cure for tuberous sclerosis, but there is a range of treatments for many of problems caused by the condition.
- epilepsy may be controlled with medication, 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 medication
- brain tumours can be surgically removed or shrunk with medication
- the facial rash can be treated with laser therapy and/or medication applied to the skin
- medication 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 mTOR inhibitors, which interrupt the chemical reactions needed for tumours to grow, may be a very 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.
Read more about treating tuberous sclerosis.
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.