Imprinting disorders may be caused by epimutations. Some subjects exhibit methylation abnormalities in several regions subject to imprinting, a condition known as multilocus imprinting disorder (MLID). The prevalence of MLID is unknown, due to variations in the methodologies used (including technique employed and number of regions studied). The phenotypic consequences of MLID are also poorly understood. Studying the methylation of all the imprinted regions would make it possible to determine the prevalence of MLID as well as its clinical consequences.