Tuberous Sclerosis is an uncommon and complex genetic disorder. It varies in the severity with which it affects people - some people are severely affected and diagnosed early, others are only found to have the condition when their child is diagnosed.
The common feature of Tuberous Sclerosis is the overgrowth of “normal” tissue in the brain and in other organs, including the skin, kidneys, heart, liver and lungs. These growths begin to form in the brain prior to birth and can interfere with brain functioning. They can cause seizures, delayed development, intellectual disability, and autistic or hyperactive behaviour. With age, these growths become hard and calcified, hence the term 'sclerosis'.
The symptoms of Tuberous Sclerosis vary from one individual to the next, depending on the severity of the condition and which areas of the body are affected.
Around one out of two people born with Tuberous Sclerosis will have an IQ in the same range as the general population. Estimates vary, but it is thought that approximately one in 7,000 to 10,000 people have Tuberous Sclerosis. There is no cure but recently approved medicine are offering new treatment options for individuals with TSC.
Tuberous sclerosis is a genetic disorder and is inherited in a dominant fashion. Everyone has two copies of every gene – one from their mother and one from their father. In a “dominant” disorder, only one copy of the gene needs to be faulty for the person to have the disorder. About 6 out of 10 cases are as a result of a spontaneous gene mutation and there is no history of TSC in the family. The faulty TSC gene may also be inherited from a parent, and a person with the condition has a 50 per cent chance of passing on the condition to each of their children.
If a child is diagnosed with Tuberous Sclerosis, other family members should be tested. This is to find out whether the child inherited the condition from one of their parents, or if the disorder has occurred for the first time in them.
Tuberous sclerosis is diagnosed using a number of tests, including:
- Physical examination.
- Eye examinations, which may reveal retinal abnormalities.
- A computerised tomography (CT) scan or magnetic resonance imaging (MRI) to look for brain growths.
- Renal ultrasound to look for cysts or benign tumours in the kidneys.
- Other possibly affected organs, such as the heart and lungs, may be checked for the presence of tuber-like growths to confirm diagnosis.
There is no prenatal test available to the general public to check the unborn baby, although echocardiography of the baby's heart may show the characteristic lesions and lead to a diagnosis of TSC. If there is a family history of TSC and the gene mutation is identified, prenatal testing and pre-implantation genetic diagnosis can be used to avoid passing on TSC to a child..
There is no cure for Tuberous sclerosis.
Historically, treatments were available to manage the symptoms that the patient experiences as they arise. More recently a new class of medicines, mTOR inhibitors, have been approved for targeted treatment of the tumours associated with TSC. These medicines offer new hope to families affected by TSC.
The effects of TSC are very varied. Many people with TSC are intellectually normal and lead perfectly normal lives; some have medical problems, epilepsy and mental ill health. There are rarely problems with mobility in TSC. Contrary to what has been believed for many years, the prognosis for patients with the condition is very good. The life expectancy for the majority of people with TS is normal, even for those with severe learning difficulties and epilepsy.
Further Information and Support
National Institute of Neurological Diseases and Stroke USA
Reviewed by Professor Kathryn North, MD, FRACP, Professor, Discipline of Paediatrics and Child Health, Faculty of Medicine, University of Sydney and Head, Neurogenetics Research Unit, The Children's Hospital at Westmead, Australia
Updated by Tuberous Sclerosis Australia, February 2015