Mutation analysis of TSC2 gene in 33 Turkish familial cases with tuberous sclerosis.

Tuberous sclerosis is an autosomal dominant multisystem disorder characterized by hamartomatous growths in different organs. Disease determining genes are localized to 9q34 (TSC1) and 16p13.3 (TSC2). Two-thirds of the cases are sporadic and result from new mutations. The aim of this study was to determine TSC2 gene mutations by Single Stranded Conformation Polymorphism (SSCP) analysis and direct sequencing in 33 familial cases with tuberous sclerosis who were followed up in the Pediatric Neurology Departments of Hacettepe University Ihsan Doğramaci and Ankara Social Security Children's Hospitals. Forty-one exons of TSC2 gene were amplified and subjected to SSCP, and sequence analysis was performed when an abnormal SSCP pattern was observed. As a result, six new mutations and nine gene polymorphisms were detected. The new mutations are G-->T mutation in exon 20, 16bp deletion in exon 29, 18bp deletion in exon 40, 538 G-->A mutation in exon 29, T-->C mutation in exon 21 and G-->A splice site mutation in exon 5. Although further studies on larger groups are needed, these results do not indicate a common region or type of mutation in the Turkish population.