Segregation and linkage analyses of Tourette's syndrome and related disorders.

Segregation and linkage analyses were performed with data from a large Tourette's syndrome (TS) multigenerational kindred. Results of segregation analyses were remarkably similar to some reported earlier and suggest that the mode of transmission is consistent with autosomal dominant inheritance. The analyses were done using three diagnostic schemes to specify affected family members (TS only; TS or chronic tics [CT]; and TS, CT or obsessive compulsive disorder [OCD]). The estimates of penetrance for the genotypes AA, Aa and aa (A denotes the susceptibility allele) in the analyses including relatives with TS, CT or OCD were 0.99, 0.99 and 0.00, respectively, for males and 0.70, 0.70 and 0.00 for females. Pairwise linkage analyses with 140 marker loci failed to identify a linked marker. However, approximately 30 percent of the genome was excluded as the site of the hypothesized locus for TS.