The Orphanet nomenclature is used to code the diagnosis of rare diseases with aspecificidentifier named the ORPHAnumber or ORPHAcode in order to facilitate data collection, research and analysis. Please see http://www.orphadata.org/cgi-bin/img/PDF/ORPHAnomenclaturexmlcontent.pdf An attribute "cycle=true" is added in the case of an auto-reference of a parent-disorder or a child-disorder for a same concept in order to avoid creating a loop. In this case, the Name and Orphanumber of parent-disorder or child-disorder are not displayed again. An attribute "cycle=true" is added in the case of an auto-reference of a parent-disorder or a child-disorder for a same concept in order to avoid creating a loop. In this case, the Name and Orphanumber of parent-disorder or child-disorder are not displayed again. Defines the association between RootDisorder and TargetDisorder. The relation goes RootDisorder to TargetDisorder. Exemples: RootDisorder "moved to" TargetDisorder ; RootDisorder "referred to" TargetDisorder.