Is there any testing needed for siblings of people who have tsc?

Perhaps: Tuberous sclerosis complex (tsc) is an autosomal dominant condition. A parent with tsc has a 50-50 chance of passing her tsc mutation to each child. Sometimes the manifestations of tsc are very subtle. To answer your very appropriate question, the best place to start is with a detailed history, family history, physical exam, and possibly brain MRI & renal ultrasound via a clinical geneticist.

TSC?: The abbreviation is not specific. If tsc stands for tuberous sclerosis, then genetic testing is available for both type 1 and 2. Given the complexities of interpreting genetic testing, all tests should be done under the care of a clinical geneticist.