Children's Hospital Colorado

Tuberous Sclerosis Complex

What is tuberous sclerosis complex?

Tuberous sclerosis complex (also known as TSC or tuberous sclerosis syndrome) is a rare, multisystem genetic disease that causes benign (noncancerous) tumors. The tumors can grow on the brain and on other organs such as the kidneys, heart, eyes, lungs and skin.

TSC disease usually affects the central nervous system and results in a combination of symptoms including seizures, developmental delay, behavioral issues, skin abnormalities and kidney disease.

The name tuberous sclerosis comes from the characteristic tube-shaped lesions that grow on the brain and calcify with age, becoming hard or sclerotic.

When might kids get tuberous sclerosis complex?

Many TSC patients show evidence of the disorder in the first year of life. However, the signs and symptoms can be subtle at first and sometimes take years to develop. As a result, TSC can be unrecognized or misdiagnosed for years.

What causes tuberous sclerosis complex?

TSC is caused by defects, or mutations, on the TSC1 and TSC2 genes. Only one of the genes needs to be affected to cause TSC.

Genes form together to make up chromosomes, which our body uses as a blueprint, telling it how to form and function. In tuberous sclerosis inheritance, these particular genes interact with proteins that help control cell growth and size.

Who gets tuberous sclerosis complex?

TSC is inherited in an autosomal dominant manner, meaning a child needs to receive only one copy of a mutated gene to develop the condition. About 40% of cases are due to genetic mutations passed down from a family member. The remaining 60% of TSC patients have a new genetic mutation that causes the disorder.

People from all ethnic groups develop tuberous sclerosis complex. Both males and females are equally affected. Tuberous sclerosis complex occurs in approximately one out of every 6,000 births. Approximately 50,000 people in the United States, and more than one million worldwide, have TSC.

Get to know our pediatric experts.

Peter Baker, MD

Peter Baker, MD


Michelle Clementi, PhD

Michelle Clementi, PhD

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Kristen Park, MD

Kristen Park, MD

Neurology - Pediatric, Neurophysiology, Neurology

Angela Starks, NP, MPH/MSPH, RN

Angela Starks, NP, MPH/MSPH, RN

Certified Pediatric Nurse Practitioner