The HTR is a volunteer twin registry of all age groups in Hungary. Since its inception in 2006, the HTR has increased its sample size due to the continuous media presence, and currently involves 1,044 twin-pairs of all age groups (50% monozygotic [MZ], 50% dizygotic [DZ], 70% women, average age 34 years), including 24 triplets and 1 quadruplet from the entire country. Through the population-based data collection efforts of the HTR, Hungary’s twin registry became the largest in Central Eastern Europe where the registry recruitment was able to focus on the whole population.

Recruitment is ongoing