Establishing a resource for genetic, epidemiological, and biomarker studies: The important role of twin registers

Twin registers are wonderful research resources for applications in epidemiology, molecular genetics, and other areas of research. New registers continue to be launched all over the world as researchers from different disciplines recognize their potential. In this chapter, we discuss multiple aspects that need to be considered when initiating a register. This encompasses aspects related to the strategic planning and key elements of research designs, promotion, and management of a twin register, including recruitment and retaining of twins and family members, phenotyping, database organization, and collaborations between registers. Information on questions unique to twin registers and twin-biobanks, such as the assessment of zygosity by genotype arrays, the design of (biomarker) studies involving related participants and the analyses of clustered data, is presented. Altogether, we provide a number of basic guidelines and recommendations for reflection when planning a twin register.