Chief of Medical Genetics and Metabolism, Massachusetts General Hospital

Co-Director Pitt Hopkins Syndrome Clinic, MGH

MGH Site Director, Undiagnosed Diseases Network

Assistant Professor of Pediatrics, Harvard Medical School

Dr. Sweetser graduated with Honors from Stanford University, then completed his MD/PhD at Washington University School of Medicine in St. Louis, and Pediatric Residency training at St. Louis Children's Hosp. He did his Medical Genetics Fellowship training at the Washington University School of Medicine in St. Louis and the University of Washington in Seattle along with a Biochemical Genetics Fellowship. He completed a Post-Doctoral Fellowship in the laboratory of Dr. Richard Palmiter. He subsequently completed a Fellowship in Pediatric Hematology/Oncology at the University of Washington. in Seattle. He is Board Certified in Clinical Genetics and Genomics, Clinical Biochemical Genetics, and Pediatric Hematology-Oncology.

Since 2003 Dr. Sweetser has been at Massachusetts General Hospital and sees patients in Medical Genetics and Metabolism as well as Pediatric Hematology/Oncology. He specializes in children and adults with metabolic disease, neurodevelopment disorders, complex undiagnosed disorders as well as those with inherited hematological disorders and children with genetic disorders predisposing to malignancies. In 2011 he was appointed as Chief of Medical Genetics and Metabolism at Massachusetts General Hospital and in 2017 was awarded the Lewis and Leslie Holmes Endowed Chair in Genetics and Teratology. The Medical Genetics program at MGH includes 11 geneticists and has over 4000 patient encounters a year and provides services to three major hospitals in the Boson area. Under his leadership the Genetics Program has markedly expanded with specialty clinics in Turner Syndrome, Williams Syndrome, Stickler Syndrome, del22q Syndrome, Hereditary Hemorrhagic Telangiectasia, CHARGE syndrome, Klinefelter syndrome, and a multidisciplinary Sensorineural Hearing Loss Clinic at the MEEI, an Autism Genetics Clinic at the Lurie Center, Pediatric Cancer Predisposition Clinic, Pitt Hopkins Syndrome, as well as a world renown Down Syndrome clinic. Dr Sweetser teaches a graduate course, “Genetics in Medicine” in the Biological and Biomedical Sciences program at Harvard and is the MGH Site Director of the Harvard Medical School Genetics Training program.

Dr. Sweetser also runs a research lab in the Center for Genomic Medicine and MGH Cancer Center investigating several genetic disorders including Pitt Hopkins Syndrome, IQSEC2 -related disorder, and leukemia. Together with Dr. Stephen Haggarty he has systematically generated and characterized patient derived induced pluripotent stem cell (iPSC) models of several inherited monogenic causes of intellectual disability and neurodevelopmental disorders developing phenotypic assays amenable to drug screening to precision targeted therapeutics. Dr. Sweetser has been a leader in the application of whole exome sequencing to clinical diagnostics and expanding clinical genetics applications throughout MGH. Dr. Sweetser is also the MGH site director for the NIH sponsored Undiagnosed Diseases Network linking 11 medical centers around the country to accelerate discovery and innovation in the way we diagnose and treat patients with previously undiagnosed diseases.