Tuberous sclerosis

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

Tumours can develop on the skin and in the:

brain
heart
eyes
kidneys
lungs

There is currently no cure for the condition, but there is a range of treatments for many of the associated symptoms. New research has shown that medicines called mTOR inhibitors may have important benefits in the future.

Read more about treating tuberous sclerosis.

Associated conditions and complications

The benign tumours that develop from tuberous sclerosis can cause a range of other associated health conditions and complications. These include:

epilepsy – a condition that causes seizures (fits)
intellectual impairment, such as below-average intelligence
learning disabilities
behavioural problems, such as hyperactivity or autism (a developmental disorder that causes problems with language and social interaction)
skin abnormalities, such as patches of light-coloured or thickened skin, or red acne-like spots
heart problems
kidney disease
lung problems
hydrocephalus – a build-up of fluid on the brain

The range and severity of these conditions can vary significantly from person to person, even among members of the same family.

Some people with tuberous sclerosis do not have many symptoms and the condition has no real impact on their quality of life.

For others, the condition can severely affect their intellectual development or cause life-threatening complications such as lung failure, and they require lifelong care.

Read more about the symptoms of tuberous sclerosis.

What causes tuberous sclerosis?

Tuberous sclerosis is a rare condition that affects 1 in every 6,000 live births worldwide. The condition is caused by mutations (changes) in one of two genes:

the TSC1 gene
the TSC2 gene

As both of these genes are involved in regulating cell growth, it is thought that the mutations are responsible for causing multiple tumours to develop.

In around a quarter of cases, a child inherits one of the mutated genes from one of their parents. In the other 75% of cases, these mutations occur for no apparent reason.

Both sexes and all ethnic groups are equally affected by tuberous sclerosis.

Read more about the causes of tuberous sclerosis.

Outlook

The outlook for people with tuberous sclerosis depends on several main factors:

whether the mutation occurred in the TSC1 or TSC2 gene – people with a mutated TSC2 gene are more likely to have more serious and wide-ranging symptoms, such as epilepsy or multiple kidney tumours, although people with TSC1 may also experience severe symptoms
being born with low intelligence – children born with low intelligence usually have epilepsy that does not respond to medication, as well as associated behavioural problems such as autism or aggressive outbursts
how severely a child is affected at first – the severity of the condition is usually clear by the time a child is five years old
a new treatment – new medicines called mTOR inhibitors may improve the outlook

Most people with tuberous sclerosis will live a normal lifespan, but a number of complications may develop that can be fatal.

People with epilepsy that is difficult to treat are at risk of a condition called sudden unexpected death in epilepsy (SUDEP). This affects about 1 in every 250 people with difficult epilepsy every year. Other serious problems include hydrocephalus, kidney or lung problems.

Read more about complications of tuberous sclerosis.