Large de novo deletion of 7p15.1 to 7p12.1 involving the imprinted gene GRB10 associated with a complex phenotype including features of Beckwith Wiedemann syndrome

We present an infant with a de novo cytogenetically visible interstitial deletion of approximately 21.9 Mb involving chromosome bands 7p15.1–7p12.1, with the loss of 119 genes confirmed by array CGH. The infant had a ventricular septal defect, hand and skull anomalies, and hyperglycaemia compatible with haploinsufficiency of TBX20, GLI3, and GCK genes, respectively. In addition, the infant had some features reminiscent of Beckwith Wiedemann syndrome including macroglossia, umbilical hernia, and a relatively large birth weight and we speculate that this is due to the deletion of GRB10, an imprinted gene on chromosome 7. This report illustrates how knowledge of genes within a deleted interval facilitates optimal medical management, can explain observed phenotypes, and stimulates research questions.