REPORT OF A CRITICAL RECOMBINATION FURTHER NARROWING THE TSC1 REGION

A large tuberous sclerosis multigenerational family segregating with m arkers on chromosome 9q from the TSC1 region was studied with a new hi ghly polymorphic marker (designated A6) from the region. A critical af fected person showed recombination with the marker, eliminating approx imately 100 kilobases from the telomeric end of the critical region, w hich contains three genes and three to four additional exons for which the associated genes have not been delineated. This information serve s to further the search for the TSC1 gene.