The rare hereditary diseases encountered in the practice of pediatricians, pediatric neurologists, and geneticists include Lesch—Nyhan syndrome associated with purine metabolic disorders caused by mutations in the HPRT1 gene encoding the enzyme hypoxanthine-guanine phosphoribosyltransferase (HGPRT). HGPRT deficiency gives rise to hyperuricemia, hyperuricemic nephropathy, and a CNS lesion reminiscent of dystonic or hyperkinetic infantile cerebral paralysis concurrent with a propensity to have

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... oaggressive behavior. The diagnosis is based on a range of history data, characteristic neurological symptoms, the detection of high blood and urine uric acid levels, and the identification of pathogenic mutagens in the HPRT1 gene. Early diagnosis contributes to timely therapy and assists in medical genetic counseling. The paper describes a clinical case of a boy with Lesch-Nyhan syndrome and elucidates the problems of diagnosis and treatment of this disease.