Novel intragenic polymorphisms in the tuberous sclerosis 2 (TSC2) gene. Mutations in brief no. 184. Online

Twenty-three unrelated patients with tuberous sclerosis have been screened for the presence of mutations in six regions of the TSC2 gene. Eight novel intragenic polymorphisms have been found, one in intron 36 and seven in intron 4, with the use of SSCP analysis. Four of these polymorphisms alter the recognition sequence of specific restriction enzymes and can be detected as RFLPs. Study in a random sample of unrelated individuals from Northern Greece, showed that these polymorphisms have mean observed and expected heterozygosity values of 0.2996 and 0.3349, respectively and could be useful for linkage analysis. It is most likely that the wild type alleles from two pairs of these polymorphisms are strongly associated. A 667 bp segment of intron 4 (954 bp) and an additional 75 bp of intron 36 (352bp) were sequenced, thus completing the sequence of both introns.