Linkage to Tourette syndrome is excluded for red-cell acid phosphatase (ACP1) and flanking markers on chromosome 2pter-2p23.

A recent linkage study of Tourette syndrome with markers in the distal region of chromosome 2p gave a contradictory result with red-cell acid phosphatase (ACP1) compared to the nearby anonymous DNA markers. A modifier gene that is suspected of leading to reduced penetrance of the gene that causes the degenerative neurologic disorder Joseph disease has been hypothesized to lie on chromosome 2p25 near the ACP1 locus. Because Tourette syndrome (TS) has also been shown to have reduced sex-specific penetrance, ACP1 typings were performed on 12 families segregating TS, and pair-wise linkage analysis was carried out. Linkage was excluded for nearly 15 cM on either side of the ACP1 locus. Unpublished exclusion data from several laboratories permit exclusion of a linkage group extending from 2pter to 2p23. Furthermore, no support for the presence of any type of modifier of TS gene expression could be seen in these data.