Attributive Especially in "Lesch-Nyhan syndrome". Designating an inherited disorder of purine metabolism characterized by abnormally high levels of uric acid, compulsive biting of the lips and fingers, mental disability, and involuntary muscular movements.
1960s. From the names of Michael Lesch and William Leo Nyhan (b. 1926), U.S. physicians, who described the syndrome in 1964 (in Amer. Jrnl. Med 36 561).