Treatment of self-injurious behaviors in Lesch-Nyhan syndrome with S-adenosylmethionine.

An 11-year-old boy with Lesch-Nyhan syndrome (LNS) had persistently injured himself by biting his lips and buccal mucosa since infancy. Risperidone was only partially effective in suppressing this behavior. Oral administration of S-adenosylmethionine (SAMe), involving increasing the dose from 400 mg to 1 g, resulted in the amelioration of self-injurious behavior and anxiety as well as marked improvement in his self-esteem, performance at school, and friendships. No adverse effects were noted. SAMe may have a favorable effect on symptoms of LNS by activating monoaminergic pathways and/or increasing the adenosine pool in the salvage pathway of guanosine monophosphate synthesis. Defects in these pathways have been essentially implicated in the neurological pathophysiology of LNS.