Further evidence for the pathogenicity of 15q24 microduplications distal to the minimal critical regions.

DNA copy number alterations in 15q24 have repeatedly been reported in patients exhibiting mild to moderate developmental delay and dysmorphic features. To date, mainly microdeletions have been described, and comparison of overlapping regions allowed the definition of minimal critical regions (MCRs) for microdeletions as well as microduplications. These MCRs are associated with distinct phenotypes. Recently, a family with a new microduplication distal to these MCRs was reported. However, for this alteration the typical phenotypical consequences could not yet be determined. Here we present another family with a nearly identical microduplication exhibiting a broad clinical spectrum including developmental delay, autistic traits and dysmorphic features. Our data suggest that microduplications adjacent and distal to the known MCRs are variable in expressivity and are associated with distinct features. They might represent a novel and recurrent microduplication syndrome.