Frequently Asked Questions
What is TSC?
Tuberous Sclerosis Complex (also commonly referred to as tuberous sclerosis or TSC) is a genetic condition that affects many organs and can cause tumors in the skin, kidney, brain, heart, eyes, lungs and other organs. The severity of TSC can range from mild, such as skin abnormalities, to severe, such as seizures, cognitive impairment or renal failure.
How common is TSC?
TSC affects approximately 50,000 people in the United States and one million worldwide, with an estimated incidence of 1 in 6,000 live births.
Genetics of TSC
TSC is caused by a mutation (gene change) in one of two genes: TSC1 and TSC2. Genetic testing for TSC at this time is able to detect mutations in the TSC1 or TSC2 genes in approximately 80% of individuals. For the other 20% of individuals without an identifiable mutation, researchers are studying ways to accurately find mutations in these two known genes and look for additional genes that may be involved.
In general, one third of individuals with TSC inherit the genetic condition from a parent. Two thirds of all cases are sporadic, or occur for the first time in a family.
TSC is inherited as an autosomal dominant genetic condition. This means that a mutation in only one copy of the gene causes the condition. Individuals with TSC have a 50% chance of passing their condition to each of their children.
What are the symptoms?
The most common symptoms of TSC are seizures and developmental delay, as well as benign tumors and lesions which can affect virtually every organ system of the body including the brain, kidneys, heart, lungs, eyes, skin, and other organs. In many instances, symptoms of TSC will be apparent in the first six months of life.
Brain and Neurological Function:
In 95% of individuals with TSC, the brain is somehow affected. This usually takes the form of cortical tubers, subependymal nodules and subependymal giant cell astrocytoma (SEGA), which can be detected by brain imaging.
Epilepsy is by far the most common medical condition in TSC, occurring in 80-90% of individuals. In about one third of individuals with TSC, epilepsy starts out as infantile spasms. Peak onset occurs at about 4-6 months of age.
Individuals with TSC have an increased risk of having neurodevelopmental and behavioral impairment. Although approximately 50% of individuals with TSC have normal intelligence, developmental delay and learning disabilities are commonly found in children with TSC. Additionally, up to 50% of individuals with TSC can develop autism.
What is ASD?
Autism Spectrum Disorder (ASD) is a group of developmental brain disorders, specifically referring to the wide range of symptoms, skills, disability or impairment that children with ASD can have. Some children are mildly impaired by their symptoms, but others are severely disabled. The disorders included in ASD are:
- Autistic disorder
- Asperger disorder/syndrome
- Pervasive developmental disorder not otherwise specified (PDD-NOS)
For more information and a parent’s guide to ASD, please visit the National Institute of Mental Health website.
How common is ASD in children with TSC?
ASD occurs in up to 50% of individuals with TSC, usually diagnosed between the ages of 2 and 4.
For more information on children with TSC and ASD, please visit the Tuberous Sclerosis Alliance website.
What is an MRI?
Magnetic resonance imaging (MRI) is a test that uses a magnetic field and pulses of radio wave energy to make images of organs and structures inside the body. For this test, the area of the body being studied is placed inside a special machine containing a strong magnet, from which digital images are produced. In some cases, contrast material may be used during the MRI scan to show certain structures and abnormal tissue more clearly. MRI of the brain is done yearly as the standard of care for children with TSC to monitor cortical tubers, subependymal nodules and to look for the development of SEGAs.
What is an EEG?
An electroencephalogram (EEG) is a test that measures and records the electrical activity of the brain. Special sensors, called electrodes, are attached to the head and hooked to a computer by wires. The computer records the brain’s electrical activity on the screen or on paper as wavy lines. The changes in the normal pattern of the brain's electrical activity may indicate seizures.
When will/did this study start and when will it end?
Enrollment begins in March 2013. We expect the study to be completed in the next five years.
Why are you doing this study?
We are doing this study because about 50% of babies who have TSC will also develop autism (ASD). We can diagnose TSC before birth but not ASD. We are hoping to learn more about the link between TSC and ASD. We will do this by looking for biomarkers (something that shows the presence of a disease like a blood test, MRI, EEG pattern, etc.) that are common in both diseases. We hope this will help us learn how to prevent or treat autism in babies who are have TSC.
Why is this study different from others? What questions do you hope this study will answer that other studies haven’t?
We hope to learn more about the link between TSC and ASD so we can identify treatments or preventive measures that will keep babies with TSC from developing ASD. We are hoping that we can learn if there are things we can see on an MRI or an EEG that will predict which babies with TSC will develop ASD.
What do you hope to learn that may be important to me as a parent?
We hope to learn which babies with TSC will go on to develop ASD so we can then begin trying to find treatments or preventive measures for those babies without putting babies with TSC who will likely not develop ASD at risk with treatments that are not necessary.
Why should I consider allowing my child to be in this study?
Up to 50% of babies born with TSC will eventually develop ASD. You can help us learn if there are ways to detect which babies will go on to become autistic, which may help babies born with TSC in the future. Your baby will be monitored very closely for the development of ASD, which may help you start ASD therapy early.
What if I would like to participate in the study, but am not close to one of the study sites?
Please let us know your location and we will make recommendations as to which study site you should travel to and make the appropriate arrangements.
Will I be reimbursed for my travel costs?
Yes. Limited compensation is available for travel costs which includes mileage, ground transportation, lodging, meals, etc. This will be discussed with you prior to study visit scheduling.
Can I withdraw from the study at any time?
Yes. Participation in this study is voluntary. You or your child may withdraw participation from this study for any reason at any time.
- What is TSC?
- How common is TSC?
- Genetics of TSC
- What are the symptoms?
- What is ASD?
- How common is ASD in children with TSC?
- What is an MRI?
- What is an EEG?
- When will/did this study start and when will it end?
- Why are you doing this study?
- Why is this study different from others?
- What do you hope to learn that may be important to me as a parent?
- Why should I consider allowing my child to be in this study?
- What if I would like to participate in the study, but am not close to one of the study sites?
- Will I be reimbursed for my travel costs?
- Can I withdraw from the study at any time?