A focal motor seizure phenomenologically manifested as a defined movement disorder in 29% of the patients from a consecutive video-EEG documented cohort as per consensus among experts: myoclonus and dystonia (10 and 9 cases, respectively) were the most common movement disorders, followed by chorea (4), stereotypies (3) myoclonus-dystonia (2), and tremor (1).
PRRT2 mutations are common in patients with PKD and are significantly associated with an earlier age at onset, longer duration of attacks, a complicated form of PKD, combined phenotypes of dystonia and chorea, and a tendency for a family history of PKD.
PRRT2 gene mutations have recently been identified as a causative gene of Paroxysmal kinesigenic dyskinesia (PKD), a rare movement disorder characterised by the occurrence of chorea, dystonia or athetosis triggered by sudden action.