Geographic differences in the incidence of Huntington's disease in Sardinia, Italy

The frequency of Huntington’s disease (HD) may vary considerably, with higher estimates in non-Asian populations. We have recently examined the prevalence of HD in the southern part of Sardinia, a large Italian Mediterranean island that is considered a genetic isolate. We observed regional microgeographic differences in the prevalence of HD across the study area similar to those recently reported in other studies conducted in European countries. To explore the basis for this variability, we undertook a study of the incidence of HD in Sardinia over a 10-year period, 2009 to 2018. Our research was conducted in the 5 administrative areas of Sardinia island. Case patients were ascertained through multiple sources in Sardinia and Italy. During the incidence period 53 individuals were diagnosed with clinically manifested HD. The average annual incidence rate 2009–2018 was 2.92 per 106 persons-year (95% CI, 2.2 to 3.9). The highest incidence rate was observed in South Sardinia (6.3; 95% CI, 4.2–9.5). This rate was significantly higher (p