Can Tuberous Sclerosis Cause Autism?
- Tuberous sclerosis (TSC) is a rare genetic disease that causes benign tumors to grow in the brain and on other vital organs such as the kidneys, heart, eyes, lungs, and skin. It commonly affects the central nervous system. In addition to the benign tumors that frequently occur in TSC, other common symptoms include seizures, mental retardation, behavior problems, and skin abnormalities.
About 40-45% of all people diagnosed with TSC are also diagnosable with autism. As many as 14% of people with autism spectrum disorders AND seizure disorder may also be diagnosable with TSC. Researchers aren't completely sure why autism and TSC seem to be connected, but it seems likely than an abnormal TSC gene may directly influence the development of autism. In other words, autism when it appears along with TSC may be caused by a genetic issue.
It is possible to inherit TSC from a parent. Most cases, though, are due to spontaneous genetic mutations. That is, a child's genes mutate even though neither parent has either TSC or a faulty gene. When TSC is inherited, it usually comes from only one parent. If a parent has TSC, each child has a 50 percent chance of developing the disorder. Children who inherit TSC may not have the same symptoms as their parent and they may have either a milder or a more severe form of the disorder.
In most cases the first clue to recognizing TSC is the presence of seizures or delayed development. In other cases, the first sign may be white patches on the skin. To diagnose TSC, doctors use CT or MRI scans of the brain, as well as an ultrasound of the heart, liver, and kidneys.
References:
"Tuberous Sclerosis Fact Sheet," NINDS. NIH Publication No. 07-1846
Hunt A, Shepherd C. A prevalence study of autism in tuberous sclerosis. J Autism Dev Disord. 1993 Jun;23(2):323-39.
Smalley SL. Autism and tuberous sclerosis. J Autism Dev Disord. 1998 Oct;28(5):407-14.
