Background Huntington’s disease (HD) is a dominant neurodegenerative disorder most common in populations of European origin. The prevalence of HD in the Greek population has been estimated at 5.4/100,000. The Athens Neurogenetics Unit, the only unit of its kind in Greece, has provided clinical assessment, diagnosis, molecular testing and genetic counselling to patients with HD from all regions of the country, acting in effect as a national reference centre for HD.

Aims To present an overview of HD in the Greek population based on clinical and genetic data collected from a national reference centre over a period of more than 20 years.

Methods Data were evaluated retrospectively from a total of 1097 subjects assessed clinically and tested genetically for the HD expansion over a period of 21 years (1995–2015) from all regions of the country. Overall, 758 of genetic tests were diagnostic and 339 predictive.

Results In total, 429 symptomatic and 159 presymptomatic subjects were found positive for the HD expansion (mean CAG2 count was 44.8, range 36–94). The male: female ratio for symptomatic subjects was 1.0 and the mean age at onset was 44.5 ± 13.3 years. Overall, 29 subjects with juvenile onset (<20 years) and 56 with late-onset HD (≥60 years) were identified. Family history was positive in 79.7%. Presenting symptoms were chorea (61.4%), behavioural and psychiatric disturbance (22.0%), cognitive decline (8.1%) and more rare symptoms (6.2%). The annual number of new genetic diagnoses, which reached a plateau around 2005, has stabilised at a mean of 18.3/year in the past decade. Areas of significantly increased prevalence (clusters) have been identified in the Southern Peloponnese, the Cycladic islands and Crete.

Conclusions The epidemiology of HD in the Greek population is similar to other European populations. The Athens Neurogenetics Unit is well placed for participation in European collaborative projects and future multicenter clinical trials in HD.