William Nyhan

William Leo Nyhan (born March 13, 1926) is an American physician who is currently Professor of Pediatrics at UC San Diego School of Medicine in La Jolla, California. He has also held positions at Johns Hopkins University School of Medicine, University of Miami School of Medicine. In addition, Nyhan has served on a number of advisory committees, pediatric advisory boards, and on the board of research foundations. His over 56 years of experience and interests in areas of research span a wide variety of disorders of amino acid metabolism. These include 4-Hydroxybutyric aciduria, 3-methylglutaconyl-Co A hydratase deficiency, multiple carboxylase deficiency, methylmalonic acidemia, and propionic acidemia. He is most-widely known as the co-discoverer of Lesch-Nyhan syndrome.

He is involved in the ongoing development of tandem mass spectrometry for use in newborn screening and research, and is involved in identifying the cause(s) of progressive neurologic disability in MMA after liver transplantation. Nyhan has studied the neuropathology of propionic acidemia (PA) including the manifestation of basal ganglia infarction and the neurologic non-metabolic presentation of PA. His research includes evaluating the use of dichloroacetate (DCA) in treating a broad range of patients with mitochondrial disease leading to lactic acidemia.