- Levodopa-induced dyskinesia most typically is choreiform in character and occurs as a peak-dose phenomenon. Less frequently, the dyskinesia may be dystonic in character and then is more likely to assume a pattern of biphasic dyskinesia or wearing-off dystonia. Levodopa-induced dystonia as a peak-dose phenomenon is distinctly less common . Levodopa-induced dystonia most frequently involves limbs, although facial and cervical involvement also may occur. Levodopa-induced dystonia involving the jaw is unusual and lateral jaw movements, as opposed to jaw opening and closing dystonia, are a most unusual manifestation.
- Many cases of myoclonus-dystonia (M-D) are due to mutations in SGCE (DYT11). For the majority of patients, myoclonus is relatively more severe than dystonia and can lead to significant functional disability. Deep brain stimulation has been chosen as a treatment option in some patients given that M-D often responds poorly to oral pharmacotherapy.
- An extensive variety of THAP1 sequence variants have been associated with focal, segmental and generalized dystonia with age of onset ranging from 3 to over 60 years. In previous work, we screened 1114 subjects with mainly adult-onset primary dystonia (Neurology 2010; 74:229-238) and identified 6 missense mutations in THAP1. For this report, we screened 750 additional subjects for mutations in coding regions of THAP1 and interrogated all published descriptions of THAP1 phenotypes (gender, age of onset, anatomical distribution of dystonia, family history and site of onset) to explore the possibility of THAP1 genotype–phenotype correlations and facilitate a deeper understanding of THAP1 pathobiology.
- The genetic cause of late-onset focal and segmental dystonia remains unknown in most individuals. Recently, mutations in Thanatos-associated protein domain containing, apoptosis associated protein 1 (THAP1) have been described in DYT6 dystonia and associated with some cases of familial and sporadic late-onset dystonia in Caucasians. We are not aware of any previous descriptions of familial dystonia in African–Americans or reports of THAP1 mutations in African–Americans. Herein, we characterize an African–American (AA) kindred with late-onset primary dystonia, clinically and genetically.