Tuberous sclerosis and cancer
Tuberous sclerosis, also known as tuberous sclerosis complex (TSC) or Bourneville disease, is a genetic disorder characterized by the development of benign tumors, called hamartomas, in various organs of the body. These tumors can lead to significant health issues, including seizures, cognitive impairment, and complications in organ function, particularly in the brain, heart, and kidneys. The condition arises from mutations in two key tumor suppressor genes, TSC1 and TSC2, with many cases occurring due to spontaneous mutations rather than inherited genetic patterns.
Tuberous sclerosis affects individuals of all ethnic backgrounds and both genders, with an estimated one million people worldwide living with the condition. Diagnosis typically involves a combination of clinical evaluations and imaging techniques such as MRI and CT scans, as there is no single definitive test for the disorder. While there is currently no cure, treatments focus on managing symptoms and may include surgical interventions, medications like mTOR inhibitors, and various supportive therapies.
The prognosis for individuals with tuberous sclerosis varies, with many leading normal, productive lives when properly managed, although untreated symptoms can lead to severe complications and reduced life expectancy. Awareness and early diagnosis are crucial for improving outcomes in affected individuals.
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Tuberous sclerosis and cancer
ALSO KNOWN AS: Tuberous sclerosis complex (TSC), Bourneville disease, epiloia
RELATED CONDITIONS: Benign tumors
DEFINITION: Tuberous sclerosis is a genetic disease characterized by the growth of benign tumors throughout the body.
Risk factors: Tuberous sclerosis develops because of a genetic mutation, but two-thirds of tuberous sclerosis cases are the result of spontaneous mutations with unknown causes rather than inherited from a parent. Children of tuberous sclerosis patients have a 50 percent chance of developing the disorder.
Etiology and the disease process: Two genes have been shown to be important in the development of tuberous sclerosis: the hamartin gene (TSC1) and the tuberin gene (TSC2). Both of these genes are tumor suppressors, and mutations that suppress their function have been linked with uncontrolled cell growth. Because these genes are thought to act in concert together, inactivation of only one gene is sufficient to produce symptoms of tuberous sclerosis.
Incidence: Tuberous sclerosis is a relatively rare disease, affecting all ethnicities and both genders equally. About one million people worldwide are estimated to be afflicted with the disease; approximately fifty thousand of these cases are in the United States.
Symptoms: The growth of benign, tumor-like nodules is a common feature of tuberous sclerosis. These growths, also termed hamartomas, have the potential to form in almost every organ, resulting in distinct consequences. For example, brain growths can lead to seizures, cognitive impairment, or behavioral problems, while hamartomas that form in and around the heart, called cardiac rhabdomyomas, can lead to valve dysfunction and arrhythmia. Kidney growths, or renal angiomyolipomas, may eventually grow so large that the normal kidney function is compromised. Many children with tuberous sclerosis exhibit small, reddish facial growths, called angiofibromas.
Screening and diagnosis: There is no particular hallmark sign used to diagnose tuberous sclerosis. Instead, the recognition of a combination of major and minor symptomatic features is used to establish a clinical diagnosis. Most cases present symptoms before the patient is one year old, though they may go unreported or be misdiagnosed. Some cases may not be discovered until adulthood due to a lack of symptoms. Magnetic resonance imaging (MRI), computerized tomography (CT) scans, and ultrasounds are used to detect or confirm the presence of tumors. In patients presenting with possible tuberous sclerosis, genetic testing may be used to confirm the diagnosis.
Treatment and therapy: No cure exists for tuberous sclerosis. Surgery has become an important approach to remove harmful nodule growths and preserve the function of the affected organ. Drugs to alleviate the symptoms may also be used, including antiepileptic drugs to control seizures. In 2022, the US Food and Drug Administration approved a sirolimus topical gel to treat facial tumors related to tuberous sclerosis. Rapalogs, a type of mTOR inhibitor, can also treat tumors and suppress seizures. Educational, occupational, and psychological therapies may be provided to aid patients. Surveillance and immediate treatment of symptoms have benefited patients with tuberous sclerosis.
Prognosis, prevention, and outcomes: The prognosis for individuals with tuberous sclerosis depends on the severity of symptoms. Many patients with mild tuberous sclerosis lead productive lives with a normal life span. However, if these patients are not treated appropriately, complications arising from hamartoma growth in vital organs can result in premature death.
Bibliography
Pounders, Ashley. “What is TSC?” TSC Alliance, www.tscalliance.org/understanding-tsc/what-is-tsc. Accessed 20 June 2024.
“Tuberous Sclerosis Complex.” National Institute of Neurological Disorders and Stroke, www.ninds.nih.gov/health-information/disorders/tuberous-sclerosis-complex. Accessed 20 June 2024.
“Tuberous Sclerosis Complex (TSC).” Boston Children's Hospital, www.childrenshospital.org/conditions/tuberous-sclerosis-complex-tsc. Accessed 20 June 2024.
“Tuberous Sclerosis - Symptoms and Causes.” Mayo Clinic, 6 Dec. 2022, www.mayoclinic.org/diseases-conditions/tuberous-sclerosis/symptoms-causes/syc-20365969. Accessed 20 June 2024.