Dr. Schwartz’s research interests focused on the causes of intellectual disabilities and birth defects. For the former, his laboratory concentrated on identifying genes responsible for X-linked intellectual disabilities (XLID). Over 700 families were enrolled in the project, in collaboration with Dr. Roger Stevenson, a senior clinical geneticist at GGC. Linkage was achieved in 72 of the families and 36 XLID genes were cloned, many in collaboration with groups spread throughout the world. Dr. Schwartz’s group identified mutations in the spermine synthase gene (SMS) which are associated with Snyder-Robinson syndrome. This gene converts spermidine to spermine, and affected males have an abnormally high ratio of these polyamines in their white cells. In December 2017, Dr. Schwartz was instrumental in bringing together a group of researchers, with various backgrounds and an interest in polyamine biosynthesis, to form a group named the ‘Polyamigos’. The purpose of the Polyamigos is to explore avenues for treatment of SRS.