Isolated limb dystonia as presenting feature of Parkin disease

Parkin related disease (OMIM 602544) is a common cause of autosomal recessive young-onset Parkinson's disease (PD). The motor phenotype encompasses parkinsonian features, dystonia, sustained response to levodopa and slow progression. It has been occasionally reported that patients may present with dystonia at onset.1 Isolated lower limb dystonia is a typical presentation of early-onset generalised dystonia, often indicating a DYT1 carrier status. DYT1 and non-DYT1 cases have also been described with onset in adulthood. It is presently unknown in how many such cases dystonia may be the presenting feature of Parkin disease. We observed a series of Parkin gene mutation carriers who had isolated limb dystonia as the presenting feature of their disorder that lasted for several years before parkinsonian features developed. We report the clinical description of eight such cases; four patients are illustrated in the online supplementary video. Parkin gene mutations were detected according to standard procedures.2 Eight had isolated dystonia at onset. These subjects had full neurological evaluation …