Our team is working on a study to better understand neurological problems, including seizures and developmental delays, that occur in children with hyperinsulinism, including HI/HA syndrome, and type 1 diabetes mellitus. The study involves a one-day visit to The Children's Hospital of Philadelphia and The University of Pennsylvania for a specialized magnetic resonance imaging scan (MRI) of the brain, an electroencephalogram (EEG), blood draw, and completion of questionnaires to evaluate development and behavior. The entire study visit is expected to take about five hours. If you are interested in learning more, please contact us at HIResearch@email.chop.edu.