TSC is caused by mutations in genes TSC1et TSC2, located respectively on chromosomes 9 and 16.
It is a genetic autosomal dominant disease.
The term "autosomal" means the gene in question is not located on the sex chromosomes (chromosomes X or Y), but on one of the other 22 chromosomes, called " autosomes ". The disease can thus appear as well in a boy than in a girl. Each person has two copies of each gene, one from his father, the other his mother.
The term "dominant" means that only one of the two copies of the gene carrying the mutation for the disease to manifest itself. The sick person has, for each design, a risk of transmitting the mutated gene to his children.