Tuberous Sclerosis

Patient Education

What is Tuberous sclerosis?

Tuberous sclerosis complex (TSC) is a genetic disorder that causes non-malignant tumors to form in many different organs, primarily in the brain, eyes, heart, kidney, skin, and lungs. The aspects of TSC that most strongly impact the quality of life are generally associated with the brain: seizures, developmental delay, intellectual disability, and autism. However, many people with TSC are living independent, healthy lives and enjoy challenging professions such as doctors, lawyers, educators, and researchers. The incidence and severity of the various aspects of TSC can vary widely between individuals even between identical twins.

How is TSC Diagnosed?

Because TSC can manifest in so many different ways, diagnosis is generally made when physicians identify any two major features of TSC in one individual. One major feature is cardiac rhabdomyoma, an abnormal growth in the heart muscle generally found in young children and sometimes found by ultrasound examination during pregnancy. Other major features include specific abnormal skin growths or skin pigmentation, specific non-malignant tumors or growths such as subependymal nodules or subependymal giant cell astrocytomas (SEGAs) in the brain, lymphangioleiomyomatosis (LAM) in the lungs, angiomyolipomas in the kidney(s), and tubers in the brain or hamartomas in the eye. Also, there are other minor features of TSC that might be diagnostic if found with a major feature in the same person. TSC can also be diagnosed by genetic testing described below.

How Many People Have TSC?

At least two children born each day will have a tuberous sclerosis complex. Current estimates place tuberous sclerosis complex-affected births at one in 6,000.

How Does a Person Develop TSC?

Tuberous sclerosis complex is a genetic disease that can be inherited from one parent with TSC or can result from a spontaneous genetic mutation. Children have a 50 percent chance of inheriting TSC if one of their parents has this condition. At this point, only one-third of TSC cases are known to be inherited. The other two-thirds result from a spontaneous and unpredictable mutation occurring during conception or very early development of the human embryo.

What Genes are Responsible for TSC?

Two genes have been identified that can cause tuberous sclerosis complex. Only one of the genes needs to be affected by TSC to be present. The TSC1 gene is located on chromosome 9 and is called the hamartin gene. The other gene, TSC2, is located on chromosome 16 and is called the tuberin gene. Laboratory research on the function of these genes over the past decade has led to new drug therapy for two types of tumors in TSC.

What Is the Normal Life Expectancy of an Individual with TSC?

Most people with TSC will live a normal life span. There can be complications in some organs such as the kidneys and brain that can lead to severe difficulties and even death if left untreated. To reduce these dangers, people with TSC should be monitored throughout their life by their physician for potential complications. Thanks to research findings and improved medical therapies, people with tuberous sclerosis complex are experiencing better health care than ever before. But more research is needed until we find a cure.

Since there is No Cure, What can be Done?

Early diagnosis and intervention can help overcome developmental delays. Data show that early seizure control in children can improve learning as compared to children without good seizure control. Advancements in research continue to bring new and improved therapeutic options. Some anti-seizure drugs can be effective in individuals with TSC. When drug treatment fails to adequately control seizures, technology can help identify the exact portions of the brain stimulating seizures and creating new therapies to help control seizures.

For tumors in the brain, surgery is sometimes used to permanently remove tumors that are relatively few in number and easily accessible by the surgeon. In other cases, drug treatment may be used to shrink brain tumors. In the fall of 2010, the FDA approved the first drug with an indication specifically for TSC to treat a type of brain tumor known as subependymal giant cell astrocytomas (SEGAs). In 2012, the same drug was approved to treat growing angiomyolipomas, a type of kidney tumor in TSC.