Earlier onset of motor deficits in mice with double mutations

DYT1 early-onset generalized torsion dystonia is an inherited movement disorder caused by mutations in DYT1 coding for torsinA with 30 % penetrance. Most of the DYT1 dystonia patients exhibit symptoms during childhood and adolescence. On the other hand, DYT1 mutation carriers without symptoms during these periods mostly do not exhibit symptoms later in their life. Little is known about what controls the timing of the onset, a critical issue for DYT1 mutation carriers. DYT11 myoclonus-dystonia is caused by mutations in SGCE coding for e-sarcoglycan. Two dys-tonia patients from a single family with double muta-tions in DYT1 and SGCE exhibited more severe symptoms. A recent study suggested that torsinA con-tributes to the quality control of e-sarcoglycan. Here, we derived mice carrying mutations in both Dyt1 and Sgce and found that these double mutant mice showed earlier onset of motor deficits in beam-walking test. A novel monoclonal antibody against mouse e-sarcoglycan was developed by using Sgce knock-out mice to avoid the immune tolerance. Western blot analysis suggested that functional deficits of torsinA and e-sarcoglycan may independently cause motor deficits. Examining additional mutations in other dystonia genes may be beneficial to predict the onset in DYT1 mutation carriers