Lesch Nyhan syndrome is a rare genetic disease of purine metabolism. It was first reported by Lesch m and Nyhan WL in 1964. Its transmission mode is recessive inheritance of X-linked chain. The incidence rate is about 1/100000 of the newborn, and the incidence of male is not related to race. In fact, it is a complete lack of hypoxanthine guanine phosphoribosyltransferase (HGPRT). The lack of this enzyme leads to the production of excess uric acid products, which are higher than those of typical gout or other hyperuricemia. The clinical feature of this disease is a kind of strange and compulsive mutilation phenomenon of one's own limbs, i.e. biting one's own lips, arms, legs, etc.