HYPERAMMONEMIC COMA IN AN ADOLESCENT GIRL - AN UNUSUAL CASE OF ORNITHINE TRANSCARBAMYLASE DEFICIENCY

Ornithine transcarbamylase deficiency (OTCD) is caused by an alteratio n of urea synthesis, linked with partial modification of the X-chromos ome, whose clinical manifestations are: lethargy, nausea, vomiting and cerebral edema. While in newborn males OTCD presents with hyperammoni emia leading to cerebral palsy with profound neurological impairment a nd eventually death, in women who are healthy carriers, it is possible to detect the disorder only through specific tests, since heterozygot e women are rarely symptomatic. We describe the case of a young woman admitted to the hospital after an episode of mental confusion with vom iting and psychomotor restlessness, which had previously occurred seve ral times during the premenstruum and lasted a few hours. A 2 day hist ory of stupor made admission mandatory. Tests carried out during the h ospital stay showed marked hyperammoniemia and unconjugated hyperbilir ubinemia, marked cerebral edema documented by a CT scan. Liver biopsy and CSF test were normal. Screening of plasma and urinary aminoacids, level of orotic acid in the urine and OTC activity in the liver, confi rmed the diagnosis of OTCD. The possibility of early diagnosis and the rapy of a disease which otherwise leads to death, emphasizes the impor tance of precise evaluation of a possible organic cause of anorexia an d behaviour disorders in young women.