Delineating the 17q24.2–q24.3 microdeletion syndrome phenotype

We present an 11-year-old girl with a 2.3 Mb de novo interstitial deletion in chromosome 17q24.2–q24.3 identified by array CGH. The phenotype in this case includes skeletal malformations (lower limb bowing, progressive scoliosis and dental abnormalities), feeding problems, mild learning difficulties, and a characteristic facial appearance. Much of the phenotype is attributable to the deletion of KCNJ2, which causes Andersen Tawil Syndrome (ATS), but the facial appearance is not typical. We hypothesise that the presence of mild channelopathy-related features seen in ATS may be explained by haplo-insufficiency, leading to a reduced number of functionally normal Kir2.1 channels. Comparison is made to previous reports describing overlapping 17q deletions, and potential candidate genes which account for the specific phenotypic similarities with this case are highlighted.

► We describe common clinical features associated with 17q24.2–q24.3 deletion. ► Features include skeletal malformations, feeding difficulties and distinctive facies. ► Common features may result from MAP2K6 and/or ABCA gene deletion. ► Arrhythmias and hypotonia seen with Andersen Tawil Syndrome were not seen. ► KCNJ2 haplo-insufficiency may explain the absence of a symptomatic channelopathy.