A Study of the Placental Methylome of Dichorionic and Monochorionic Monozygotic Twin Pairs to Establish a Timeline of Epigenetic Programming

Adult twins will be asked to send saliva samples in a reply envelope to Maastricht University, department of Genetics and Cell Biology, where they will be frozen and stored before analysis. DNA will be extracted from the saliva using a commercially available kit according to the manufacturer's instructions.

Along with saliva samples, adult twins, will be asked to complete a questionnaire about their health. Study subjects will be asked to self-report height and weight. Additionally, questions will focus on cardiometabolic risk, including questions about smoking, physical activities, medical diagnoses, current medications, family history of cardiometabolic disease, and for female twins an obstetric and gynaecological history, including number of pregnancies and pregnancy complications (such as gestational diabetes and pre-eclampsia). The questionnaire will take the form of a self-completed, web-based questionnaire which will be hosted by the Qualtrics platform (Qualtrics.com). This platform is supported by the University of Maastricht due to its security and privacy measures.