Towards rational drug treatment of Lesch-Nyhan disease.

Lesch-Nyhan disease (LND) is a rare X-chromosomal purine metabolism disorder. LND is characterized by self-injurious behavior (SIB) for which there is no drug treatment. This commentary places a recent clinical study by Khasnavis et al. (Mol. Genetic. Metab., in press) on drug treatment of SIB into a broader context. Although the study by Khasnavis et al. was no break-through in terms of "positive" results, nonetheless, it presents an excellent model of how clinical studies in general and clinical studies on rare diseases should be conducted.