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What Is TSC?

Tuberous sclerosis complex (TSC) can cause benign tumors in different places in your body at different times in your life.


TSC Is a Lifelong Disease

In different stages of your life, TSC may cause tumors in your brain, kidneys, lungs, heart, skin, and eyes. These tumors are not cancerous, but they can create serious complications if they are not watched and taken care of. Your doctor can help you treat them if they cause problems. TSC can also cause neurologic (brain) issues such as seizures and learning disabilities.

TSC may cause tumors in your brain, kidneys, lungs, heart, skin, and eyes.


Brain—About 80% of people with TSC have SEN brain tumors, and up to 15% have SEGA brain tumors


Kidneys—About 80% of people with TSC have kidney tumors


Skin—More than 90% of people with TSC experience skin problems


Lungs—Nearly 40% of women with TSC have lung tumors


Heart—About 50% of babies with TSC are born with heart tumors


Eyes—40% to 50% of people with TSC have eye tumors


Teeth—100% of adults with TSC have dental pits in their teeth


SEN, subependymal nodule; SEGA, subependymal giant cell astrocytoma.

Turn to us for support.

TSC is a lifelong disease that can seem complicated. But you are not alone. The more you learn, the better you can manage your health.


How Do Doctors Diagnose TSC?

TSC is a challenge to diagnose and treat because it affects everyone in a different way:

  • No 2 people have the same symptoms
  • Some people have very mild symptoms, while others have serious ones
  • and some people may have just a few tumors in one place, like the kidneys, while others may have many tumors affecting several places, such as the brain and lungs

Doctors will make a definite diagnosis of TSC if you have:

  • 2 major areas affected
  • or 1 major and 2 minor areas affected

Doctors will make a possible diagnosis (meaning you might have TSC) if you have:

  • Either 1 major area affected or 1 major and 1 minor area affected
  • or at least 2 minor areas affected

Common Areas Affected by TSC

TSC complications are divided into major and minor signs based on how common they are. The major signs occur in the majority of people with TSC, and the minor ones occur in smaller percentages of people. This separation of major and minor signs helps doctors determine who has TSC.


brain illustration


  • Small tumors  called SENs (subependymal nodules) or large tumors called SEGAs (subependymal giant cell astrocytoma)
  • Seizures

kidneys illustration


  • Tumors (renal angiomyolipomas) 


  • Cysts
skin illustration


  • Small bumps on your face
  • An area of thick, pebbly skin on your back
  • Small lumps around fingernails and/or toenails
  • Small spots on arms and/or legs
  • Pink patches of raised skin on your forehead


  • Patches that are lighter than the rest of your skin, called "confetti" skin lesions
lungs illustration


  • LAM lung disease (lymphangioleiomyomatosis)

heart illustration


  • Tumors in infants called cardiac rhabdomyomas 

eye illustration


  • Small tumors in the back of the eye (can only be seen by an eye doctor)
  • Discolored spots
teeth illustration


  • Small pits in your teeth
  • Skin growing over teeth or gums
Other areas
skin illustration Minor
  • Noncancerous masses on other organs

What Is the Cause?

TSC can occur randomly; 2 of every 3 people with TSC have the genetic disorder that developed on its own, without a family connection.

One of every 3 people with TSC has the genetic disorder passed down from a parent.

How Do People Get TSC?

There are about 20,000 genes in everyone’s body. Each person has genes called TSC1 and TSC2. These genes make proteins to control mTOR and control cell growth.

People with TSC have a defect in TSC1 and TSC2, so their bodies do NOT make proteins to control mTOR. Cells grow out of control, and tumors or seizures can happen.


image of cell growth due to TSC


mTOR, mammalian target of rapamycin.

The Story of TSC

Watch a short animated film about how TSC occurs.

The Story of TSC

Watch a short animated film about how TSC occurs.

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