I was pleased to see the study by Gelernter et al 1 concerning the role of the dopamine D 2 receptor ( DRD2 ) gene in Tourette syndrome (TS) because the authors so nicely verified our previous studies demonstrating a role the DRD2 gene in TS and because they illustrated some of the issues concerning association vs linkage studies in neuropsychiatric disorders. I felt that it was necessary to write this letter because the way in which the results were reported may have left the wrong impression with readers who are not familiar with the field. In 1991, we 2 reported that the prevalence (percent with the 11 or 12 genotype) of the D 2 A1 allele in 147 non-Hispanic white TS probands was 44.9%. This was significantly greater than the prevalence of 24.5% in 314 non-Hispanic white control subjects ( P =.0001). Subsequently, we 3 reported on an enlarged set of 220