FGFR3 and mesomelic dysplasia: The disorder classification mechanism also differs. Orphanet uses the hierarchy to denote both grouping of disorders, e.g., several disorders are part of the FGFR3 Chondrodysplasia Group, as well as sub-typing, e.g., Mesomelic dysplasia, Korean type is (conceptually) a type of Mesomelic dysplasia.