ABSTRACT
Familial dystonias have been listed with progressive numbering preceded by the DYT code (meaning ‘dystonia’; Table 3.2). This list was originally supposed to include only primary dystonias, but currently encompasses several heterogeneous conditions, such as unmapped PTD familial loci (e.g. DYT2 and DYT4), heredodegenerative dystonias (e.g. DYT3), dystoniaplus syndromes (DYT5 and DYT11, DYT12, DYT14), and paroxysmal dyskinesias or choreoathetosis (DYT8, DYT9, DYT10). Therefore, of the 15 DYT loci, only six refer to PTDs, namely those marked as DYT1, DYT2, DYT4, DYT6, DYT7, and DYT13. With the exception of DYT2, all PTDs are inherited as a dominant trait with reduced penetrance.
