Atypical movement disorders in the early stages of Huntington's disease: clinical and genetic analysis

Huntington's disease (HD) is notably difficult to diagnose in the early sta ges. One reason is that the early clinical manifestations of HD vary widely and sometimes have an atypical onset. In this paper we primarily sought in formation on affected patients who initially presented with movement disord ers other than chorea. We also investigated atypical motor presentations in relation to triplet CAG expansions. After reviewing the clinical records o f two neurological centres, we identified patients with a final, documented diagnosis of HD and selected for study 205 patients according to their ons et of motor manifestations. CAG repeats were analysed. Of the 205 patients studied, 15 had atypical motor symptoms at onset. In this group we identifi ed three types of initial clinical manifestations other than chorea: parkin sonism, ataxia and dystonia. We conclude that HD patients may have differen t motor manifestations at the initiation of the illness. Patients with atyp ical movement disorders in the early stages have larger CAG expansions and an earlier age at onset than HD patients with typical onset chorea.