Lesch, Michael (1939–2008),
and Nyhan, William Leo (born 1926),
American pediatricians. Nyhan held the position of professor of pediatrics at several medical schools, including Johns Hopkins. He had a major interest in the disorders of amino acid metabolism and routinely analyzed blood and urine for amino acids. The urine of a pair of patients, two brothers, was found to contain urate crystals. In addition, the brothers were suffering from an obvious but unknown neurological disorder. Nyhan, aided by Lesch, a student research assistant, began investigating urate metabolism and the characteristics of the previously unrecognized genetic disorder exhibited by their two cases. Lesch published a description of the Lesch-Nyhan syndrome in 1964. This report laid the groundwork for the discovery in 1967 of the absence of hypoxanthine-guanine phosphoribosyltransferase in children affected with the syndrome.