In a family with tuberous sclerosis, genetic tests can be done to see whether other family members have the disorder. The fastest and simplest genetic test is to look for a known gene change causing TS in a specific family. If known, all siblings and other at-risk relatives can be tested for just that change. If a child is diagnosed with tuberous sclerosis, parents should undergo testing. Parents may have an altered TSC1 or TSC2, but may be undiagnosed because they have mild symptoms or they are mosaic for the disorder. Mosaicism is when an altered gene only appears in a percentage of a person’s cells. Sometimes, people are mosaic for a disorder and do not have any symptoms, but can potentially pass on the disorder to their children. If the underlying changes in the TSC1 or TSC2 genes are not known in a family, then molecular genetic testing, which are tests that look for changes to genes, can be performed on an affected individual.
A genetic counselor or medical geneticist with experience in tuberous sclerosis can provide advice about how a confirmed diagnosis can affect other family members. Medical geneticists can be found through the American College of Medical Genetics and a genetic counselor can be found through the National Society of Genetic Counselors.
