An unusually low prevalence of Huntington's disease in Iceland

Objectives: Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder characterized by involuntary movements and psychiatric disturbances, found worldwide, with a variable prevalence. The purpose of this study was to determine the history of HD in Iceland and determine the prevalence and incidence of HD.

Materials and methods: Clinical information was obtained from general, neurologic, and psychiatric hospitals, practicing neurologists, general practitioners, and family members of affected individuals.

Results: Twenty-seven individuals were identified with typical symptoms of HD from the 1850s to 2007. All but one sporadic case are descendants of a husband and wife living in the early and mid-19th century. The point prevalence of HD in Iceland is 1.0 per 100,000 individuals.

Conclusions: The prevalence of HD in Iceland is markedly lower than in the neighboring countries (Norway and the British Isles), where Icelanders originate from.