A mutation screen of the TSC1 gene reveals 26 protein truncating mutations and 1 splice site mutation in a panel of 79 tuberous sclerosis patients.

The entire coding region of the TSC1 gene has been screened for mutations in 79 unrelated patients with tuberous sclerosis. Causative mutations have been found in 27 of these patients and five other variations in the gene have been identified. 26 of the mutations are predicted to cause premature truncation of the protein product of the gene and one mutation is in a splice site. The mutation screen has revealed that TSC1 mutations are rarer in sporadic tuberous sclerosis patients than in familial cases. We have also found that the only previously described case of non-penetrance can no longer be described as such, and that a single ungual fibroma is not necessarily diagnostic of tuberous sclerosis, important findings for the genetic counselling of tuberous sclerosis patients.