De novo dir dup/del of 18q characterized by SNP arrays and FISH in a girl child with mixed phenotypes

About seven critical regions along the whole 18q have been proposed for Edwards syndrome (ES) / trisomy 18 (T18) phenotype (Boghosian-Sell et al. 1994; Nguyen-Minh et al. 2013). In contrast, hemizygosity for 18q22.3-18qter region has been linked to most of the features of 18q syndrome (Feenstra et al. 2007; Cody et al. 2009). Moreover, combination of both a partial gain and deletion within the same 18q seems to be fairly rare. Here we report on the rst case of de novo 18q direct duplication (34.9 Mb) / deletion (8.8 Mb) in a girl child with combined phenotypes related to both syndromes as seen in other duplication/deletion complex rearrangements (Neira et al. 2012). Since these complex rearrangements usually exhibit an inv dup/del conguration derived from a U-type exchange, our ndings and observations suggest variations of that mechanism for leading to the conguration observed here.