Dr. O’Sullivan is a first year adult and pediatric endocrinology fellow at the University of Chicago. She was born and raised in a south suburb of Chicago, Tinley Park, IL. She graduated from the University of Notre Dame and went on to receive her medical degree from Loyola University Stritch School of Medicine in Maywood, IL. She completed a dual residency in Internal Medicine and Pediatrics at the University of California, San Diego. Her clinical practice focuses on general adult and pediatric endocrinology—which includes disorders of the thyroid and adrenal glands, diabetes, growth, and obesity.