William S. Sly (1932–2025): A compassionate pioneer in biochemical genetics

William S. Sly, MD (1932-2025) was a biochemical geneticist who received his medical degree from Saint Louis University. He received additional training at the NIH with several members of the National Academy of Science and Nobel Prize winner Marshall Nirenberg. He is best known for discovering mucopolysaccharidosis type VII and developing a Food and Drug Administration-approved treatment for it. He served in several long-term leadership roles and won many accolades, including the Passano Foundation Award and induction into the National Academy of Sciences. Sly was equally well known as a kind and caring person who always made time for family, friends, colleagues, and patients. He is the personification of the caring and compassionate physician-scientist.