Definition of Tuberous sclerosis:

Tuberous sclerosis is a group of two genetic disorders that affect the skin, brain/nervous system, kidneys, and heart, and cause tumors to grow. The diseases are named after a tuber- or root-shaped growth in the brain.

Causes, incidence, and risk factors:

Tuberous sclerosis is inherited. Changes (mutations) in two genes, TSC1 and TSC2, are responsible for most cases of the condition.

Only one parent needs to pass on the mutation for the child to get the disease. However, most cases are due to new mutations, so there usually is no family history of tuberous sclerosis.

This condition is one of a group of diseases called neurocutaneous syndromes. Both the skin and central nervous system (brain and spinal cord) are involved.

There are no known risk factors, other than having a parent with tuberous sclerosis. In that case, each child has a 50% chance of inheriting the disease.