Lesch Nyhan syndrome, also known as self destruct syndrome, is an X-linked recessive congenital purine metabolic defect caused by hypoxanthine guanine phosphoribosyltransferase (HGPRT) deficiency. Without this enzyme, hypoxanthine and guanine can not be converted into IMP and GMP, but can be degraded into uric acid. Hyperuricemia causes early kidney stones and gout symptoms gradually. The patients have mental retardation and characteristic forced self mutilation.