Linkage of the tuberous sclerosis locus to a DNA polymorphism detected by v-abl

Linkage analysis was undertaken in six families with tuberous sclerosis (TS) using a restriction fragment length polymorphism detected by v-abl. No recombinants were observed in 13 informative meioses (four phase known) giving a maximum lod score of 3.18 at zero recombination (confidence limits 0 to 0.15). This provides further evidence for the assignment of TS to 9q34 and should facilitate cloning of the structural gene, genetic counselling, and first trimester prenatal diagnosis.