This review focuses on the eight monogenic primary dystonias, six of which are associated with an early-onset generalized phenotype (DYT1, 2, 4, 6, 16 and 17), while the remaining two are characterized by an adolescent- or adult-onset focal or segmental form of dystonia (DYT7 and 13).
To evaluate the contribution of these genetic loci to other families with familial "non-DYT1" dystonia five large families with dystonia were studied using genetic markers spanning the DYT6 and DYT7 regions.
The data also indicate that this dystonia mutation (DYT7) is the predominant cause of IFD, at least in this area of Northwest Germany, and that its location can be narrowed from a 30- to a 6-centimorgan region close to marker D18S1098.