What is Tuberous Sclerosis Complex (TSC)?
TSC is a genetic disorder that causes non-malignant tumors to form in many different organs, primary in the brain, eyes, heart, kidney, skin and lungs
What Does it look like?
The name tuberous sclerosis comes from the characteristic tuber or potato-like nodules in the brain, which calcify with age and become hard or sclerotic. The disorder--once known as epiloia or Bourneville's disease--was first identified by a French physician more than 100 years ago.
How common is it?
- The disorder affects as many as 25,000 to 40,000 individuals in the United States and about 1 to 2 million individuals worldwide, with an estimated prevalence of one in 6,000 newborns
- TSC occurs in all races and ethnic groups, and in both genders
- Many TSC patients show evidence of the disorder in the first year of life. However, clinical features can be subtle initially, and many signs and symptoms take years to develop. As a result, TSC can be unrecognized or misdiagnosed for years
What causes TSC?
TSC is caused by defects, or mutations, on two genes-TSC1 and TSC2. Only one of the genes needs to be affected for TSC to be present. The TSC1 gene, discovered in 1997, is on chromosome 9 and produces a protein called hamartin. The TSC2 gene, discovered in 1993, is on chromosome 16 and produces the protein tuberin.
Is TSC inherited?
Although some individuals inherit the disorder from a parent with TSC, most cases occur as sporadic cases due to new, spontaneous mutations in TSC1 or TSC2. In this situation, neither parent has the disorder or the faulty gene(s). Instead, a faulty gene first occurs in the affected individual.
What are the signs and symptoms of TSC?
- TSC can affect many different systems of the body, causing a variety of signs and symptoms
- Signs of the disorder vary depending on which system and which organs are involved
- The natural course of TSC varies from individual to individual, with symptoms ranging from very mild to quite severe. In addition to the benign tumors that frequently occur in TSC, other common symptoms include seizures, cognitive impairment, behavior problems, and skin abnormalities. Tumors can grow in nearly any organ, but they most commonly occur in the brain, kidneys, heart, lungs, and skin. Malignant tumors are rare in TSC. Those that do occur primarily affect the kidneys
How is TSC diagnosed?
- The diagnosis of TSC is based upon clinical criteria. In many cases the first clue to recognizing TSC is the presence of seizures or delayed development. In other cases, the first sign may be white patches on the skin (hypomelanotic macules) or the identification of cardiac tumor rhabdomyoma
- Diagnosis of the disorder is based on a careful clinical exam in combination with computed tomography (CT) or magnetic resonance imaging (MRI) of the brain, which may show tubers in the brain, and an ultrasound of the heart, liver, and kidneys, which may show tumors in those organs
- In infants TSC may be suspected if the child has cardiac rhabdomyomas or seizures (infantile spasms) at birth. With a careful examination of the skin and brain, it may be possible to diagnose TSC in a very young infant. However, many children are not diagnosed until later in life when their seizures begin and other symptoms such as facial angiofibromas appear
How is TSC treated?
- There is no cure for TSC, although treatment is available for a number of the symptoms
- Antiepileptic drugs may be used to control seizures
- Because TSC is a lifelong condition, individuals need to be regularly monitored by a doctor to make sure they are receiving the best possible treatments. Due to the many varied symptoms of TSC, care by a clinician experienced with the disorder is recommended
What is the prognosis?
- The prognosis for individuals with TSC is highly variable and depends on the severity of symptoms
- Those individuals with mild symptoms usually do well and have a normal life expectancy, while paying attention to TSC-specific issues. Individuals who are severely affected can suffer from severe mental retardation and persistent epilepsy
- All individuals with TSC are at risk for life-threatening conditions related to the brain tumors, kidney lesions, or LAM. Continued monitoring by a physician experienced with TSC is important. With appropriate medical care, most individuals with the disorder can look forward to normal life expectancy
For more information, please visit: http://www.tscanada.ca/