The Qatar Twin Registry (QTR): The First Twin Registry in the Arab World.

Populations of Arab ancestry remain underrepresented in global twin studies. These populations are described by distinct genetic characteristics, high consanguinity, and strong familial relatedness. To contribute to diversity in genetics and twin research, the Qatar Twin Registry (QTR) was established as the first national twin registry in the Arab world and the second in the Middle East and North Africa. The QTR is a prospective and retrospective cohort study developed by Qatar University in collaboration with the Qatar Precision Health Institute (QPHI). The registry integrates with Qatar's national biobank and whole-genome sequencing infrastructure to enable large-scale twin-based research. Participants contribute comprehensive health, developmental, psychosocial, and lifestyle information, along with biological samples collected through clinic-based assessments and home visits. QTR marks a milestone in regional genetic and epidemiological research. Leveraging and linking to Qatar's national biobank and genomic infrastructure, it establishes a sustainable framework for investigating heritability, gene-environment interactions, and complex diseases in an underrepresented Arab population, contributing to global precision medicine efforts.