Mowat-Wilson syndrome presenting with Shone's complex cardiac anomaly

A female infant, who was diagnosed antenatally with complex heart disease, confirmed to be Shone's complex postnatally, underwent bilateral pulmonary artery banding, patent ductus arteriosus stent insertion and balloon aortic valvuloplasty soon after birth. She was found to have bilateral megaureters, left hydronephrosis and asplenia. She was on lifelong prophylactic antibiotics and extra vaccines. She had two episodes of pseudo-obstruction of the small bowel, but barium follow-through was normal. She also had a large bowel obstruction and work-up for Hirschsprung disease confirmed the diagnosis. It was noticed that she had developmental delay and hypotonia, together with subtle dysmorphism. She also had failure to thrive and difficulty feeding. Exome sequencing revealed a diagnosis of Mowat-Wilson syndrome (MWS). This case shows a previously undescribed association of Shone's complex, a complex left-sided obstructive heart defect, and MWS. It also highlights the usefulness of trio-exome sequencing in detecting such rare mutations.