Orphanet rare-disease nomenclature id Orphanet_217340 (17q21.31 microduplication  syndrome) can be described as follows. The newly described 17q21.31 microduplication syndrome is associated with a broad clinical spectrum, of which behavioral disorders and poor social interaction seem to be the most consistent. Also known as: Dup(17)(q21.31), Trisomy 17q21.31.