What is Tuberous Sclerosis?

Tuberous sclerosis is a genetic disease that causes benign tumors to develop in different parts of the body.

The name is derived from the Latin and Greek terms “tuber”, which means swelling and “skleros”, which means hard. The “tubers” were first discovered in the brains of patients and were recorded in 1880 by Désiré-Magloire Bourneville.

It is not limited to the brain however, and can affect multiple body systems. Benign tumors may occur in or around vital organs such as the:

• Brain
• Heart
• Eyes
• Kidneys
• Lungs

It is a rare condition that affects approximately 1 live birth in every 6000 throughout the world. The majority of cases occur without predictable reason, although 25% of cases appear to have inherited the gene mutation from immediate relations.

The current management of the condition involves symptomatic treatment, as there is no known effective cure. Some medications, such as mTOR inhibitors, may offer a long-term benefit in the future.

Cause

Tuberous sclerosis is caused by mutations of either the TSC1 or TSC2 gene, which are responsible for encoding the hamartin or tuberin proteins respectively. These proteins play an important role in the regulation of cell growth, acting as tumor growth suppressants that regulate cell proliferation and differentiation.

A mutation in these genes would, therefore, affect the ability of the individual to regulate cell growth and may cause the development of tumors.

Symptoms and Complications

The severity of the symptoms depends on the individual and genetics. Some people with tuberous sclerosis do not note any major symptoms, whereas others are greatly affected.

Although the tumors that occur as a result of tuberous sclerosis are benign, there are several complications that may present, including:

• Epileptic fits or seizures
• Reduce cognitive function and learning disabilities
• Behavioral abnormalities (e.g. hyperactivity or autism)
• Skin changes, including color and thickness
• Problems with specific organs (e.g. heart, kidney or lungs)
• Hydrocephalus

The majority of people with tuberous sclerosis live a relatively normal life in regards to length and quality of life. However, some people experience severe complications that may limit this.

Management

As tuberous sclerosis affects multiple systems and is a long-term condition, a multidisciplinary team is usually needed to manage the symptoms. It is important that individuals affected by the condition are assessed for disorders that may affect their behavior, development or psychological status as they grow up.

As there is no cure, specific symptoms are usually addressed in the management of care to improve quality of life.

• Seizures associated with epilepsy complications, medications may offer a benefit to help in the control of seizures. When pharmacological treatment is not effecting, vagus nerve stimulation and surgery may also help.

• For patients that suffer from pulmonary lymphangioleiomyomatosis, a beta2 agonist inhaler (e.g. salbutamol) may help to reduce symptoms. Alternatively, some patients have better results with oral hormonal medications, such as progesterone, buserelin or tamoxifen.

• For severe pneumothorax, insertion of a chest drainage system may be required to manage symptoms.

• For renal disease, antihypertensive medication may offer a benefit.

• For bleeding injuries or severe skin lesions, treatment should be sought as soon as possible. Surgical excision, laser therapy or topical treatments may be preferable, depending on the specific circumstances.

• If oral fibromas cause symptoms, they may be surgically removed, although it is possible that they will recur at a later date.

References

• http://www.ninds.nih.gov/disorders/tuberous_sclerosis/detail_tuberous_sclerosis.htm
• http://www.patient.co.uk/pdf/2892.pdf#
• http://www.betterhealth.vic.gov.au/Bhcv2/bhcarticles.nsf/pages/Tuberous_sclerosis_complex_(TSC)?open
• http://www.nhs.uk/conditions/tuberous-sclerosis/Pages/Introduction.aspx
• http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4058297/