Abstract
A 35-month-old boy with non-mosaic Patau syndrome presented in diabetic ketoacidosis and was diagnosed with type 1 diabetes mellitus. A decision to treat this unanticipated medical problem was made in conjunction with the child's parent, and he improved with fluid resuscitation and insulin treatment. Acute kidney injury with hypernatraemia complicated his treatment, but this resolved with careful intravenous fluid management. The child survived and was followed up in the diabetes clinic where ongoing management was complicated by persistent fetal haemoglobin, which meant that glycated haemoglobin could not be used to gauge his glucose control.