Prevalence of Huntington's disease in Southern Sardinia, Italy

Background: The frequency of Huntington's disease (HD) may vary considerably, with higher estimates in non Asian populations. In Italy, two recent studies performed in Ferrara county and Molise provided different prevalence estimates, varying from 4.2 × 105 to 10.8 × 105. Here we present a study performed in the Southern part of Sardinia, a large Italian mediterranean island that is considered a genetic isolate. Methods: The study area included the two neighbouring counties of South Sardinia and Cagliari with 353,830 and 431,955 inhabitants respectively on December 31st, 2017 (prevalence date). Case-patients were ascertained through multiple sources in Sardinia and Italy. Results: We identified 54 individuals with HD, of whom 47 were alive on prevalence date. The resulting prevalence rate was 5.98 × 105 in the overall study area, however with marked variations between South Sardinia and Cagliari (9.6 × 105 vs. 3.0 × 105, p = 0.02). In the two study areas, we found similar CAG repeat length in normal alleles (17.5 ± 2.1 vs. 17.7 ± 2.2, p = 0.5). Conclusions: The overall prevalence of HD in Sardinia is close to the correspondent estimates in Europeans. Our findings also highlighted the possibility of local microgeographic variations in the epidemiology of HD.