Diagnosis of Tuberous Sclerosis Complex (TSC) is currently made after a series of tests have been carried out: a brain MRI or CT Scan, renal ultrasound, echocardiogram of the heart, EKG, eye exam and a Wood’s Lamp evaluation of the skin. Genetic testing is another tool used by doctors and genetic counselors. Molecular genetic testing is available for many inherited diseases. There are three primary uses for this DNA testing: 1) confirmation of diagnosis made on clinical grounds; 2) ease of testing for other at-risk family members; and 3) prenatal diagnosis.
Two genes have been identified that can cause tuberous sclerosis complex. Only one of the genes needs to be affected for TSC to be present. The TSC1 gene is located on chromosome 9 and is called the hamartin gene. The other gene, TSC2, is located on chromosome 16 and is called the tuberin gene. Researchers are now trying to determine what these genes do and how a defect in these genes causes tuberous sclerosis complex.
Both the TSC1 and TSC2 genes are believed to suppress tumor growth in the body. When either of these genes are defective, tumors are not suppressed and tuberous sclerosis complex results. The genes also play a role in the early fetal development of the brain and skin.