PRO48 THE EPIDEMIOLOGY OF HUNTINGTON'S DISEASE IN US, EU5 AND JAPAN: A SYSTEMATIC LITERATURE REVIEW

Abstract

Huntington’s disease (HD) is a life threatening autosomal dominant neurodegenerative disorder caused by an expanded cytosine-adenine-guanine triplet repeat in the Huntington gene, which encodes an abnormal polyglutamine expansion in the Huntington protein. Literature suggest that HD incidence and prevalence varies globally. Our aim was to conduct a systematic literature review (SLR) to describe the incidence and prevalence of HD confirmed by genetic mutation testing. A comprehensive search was conducted from 2011-2019 using biomedical databases (MEDLINE®, EMBASE®). Studies published prior to 2011 were identified by bibliographic searching of published SLRs’. Additional web-based searches were performed to identify evidence from registries, conferences and grey literature. We included studies from 1993 onwards as identification of the genetic mutation for HD started in 1993, and literature suggests that studies conducted prior to this may therefore underestimate the true prevalence of HD. The quality assessment of relevant studies was conducted, and data was extracted. A total of 21 studies reported data for US (2), UK (8), Spain (3), Italy (5), and Japan (3). Relevant literature was not available for France and Germany. Three studies were assessed as high quality (UK-2; Italy-1) and remaining 18 studies (US-2; UK-6; Italy-4; Spain-3; Japan-3) were of medium quality. The prevalence rates in UK, Italy, Spain, and Japan were 12.3, 10.85, 5.0 and 0.7 per 100,000 respectively. No studies were identified for the prevalence of HD in the general US population. The HD prevalence has increased over time in UK (6.4 in 1993- 12.3 in 2010) and Japan (0.65 in 1993- 0.7 in 2015). The annual incidence rate in US, UK, Italy and Spain were 1.59, 0.72, 0.34 and 0.47 per 100,000 persons. HD prevalence was lower in Japan compared to Western countries. Genetic, demographic and methodological differences among studies could be the reasons for geographic and ethnic variations.