Persuasive- the double cousin relationship will be represented via pedigree and using "cousin" code. To be more specific, the rolecode in V3 has its clear definition on most bilateral pedigree relationship. To imply two persons in pedigree is a double cousin relationship (i.e. they are siblings biologically) We provide an extension for use cases where sibling relationship can be found by using the code. The extension can be found at profile whose name is : family-member-history-genetics-sibling The example will be shown at here In this case, we provide a use case where we can use extension to identify that subject's paternal grandmother will be biological sister with subject's maternal grandmother, while subject's paternal grandfather will be biological brother with subject's maternal grandfather. (The extension cannot be displayed by website so far, you need check source code to see this usage) The attachment is the pedigree tree in this case. In this resolution we also modify the structure of profile which might be incompatible with STU3 Ballot version.