Dr. Casas attended medical school and completed his residency at the University of Oklahoma College of Medicine.

Dr. Casas was the first fellow in the University of Oklahoma College of Medicine's Pediatric Endocrinology Fellowship program after the program's accreditation in 2001. Dr. Casas graduated from the program in 2006.

Dr. Casas is currently a Pediatric Endocrinologist at the Sanford Medical Center-Fargo.