PAFAH1B1 and Williams syndrome: In still other syndromes, haploinsufficiency of one gene in the deleted region explains only some specific feature(s); haploinsufficiency of the elastin gene accounts for the cardiac defects in Williams-Beuren syndrome (deletion of 7q11.23; OMIM 194050) [33] and haploinsufficiency of the LIS1 gene explains the lissencephaly of Miller-Dieker syndrome (deletion of 17p13.3; OMIM 247200) [34], [35].