Autosomal dominant myoclonus-dystonia and Tourette syndrome in a family without linkage to the SGCE gene

The objective of this study was to report clinical details and results of genetic testing for mutations in the ε-sarcoglycan (SGCE) gene, the Slit and Trk-like 1 (SLITRK1) gene and for linkage to the DYT15, DYT1, and DRD2 gene loci in a family with autosomal dominant myoclonus-dystonia (M-D) and Gilles de la Tourette syndrome (GTS). Fourteen family members, from three generations, underwent a detailed clinical assessment and donated DNA samples. The SGCE and the SLITRK1 gene were sequenced and investigated by gene dosage analysis in selected family members. Linkage to the SGCE, DYT15, DYT1, DRD2, and SLITRK1 loci was also tested. Results: We included three healthy and 11 affected family members with M-D (n = 3), dystonia alone (n = 2), GTS (n = 1), tics (n = 1) or a combination of these with obsessive compulsive disorder (OCD) (M-D + OCD: n = 2; dystonia+OCD: n = 1; M-D + GTS + OCD: n = 1). There was no linkage to the SGCE, DYT15, DYT1 or DRD2 loci. No changes were found in the SLITRK1 gene. The presence of both M-D and GTS in one family, in which all known M-D loci and a recently discovered GTS locus were excluded, suggests a novel susceptibility gene for both M-D and GTS.