Ornithine transcarbamylase (OTC) deficiency is an X-linked inherited disease and the most common inborn error in urea synthesis in humans. In adult heterozygous patients, partial OTC deficiency can be responsible for life-threatening hyperammonemic coma, with a frequency of 15 %. We report the clinical course of a heterozygous female patient and discuss the therapeutic options, including hemodialysis and continuous arteriovenous hemofiltration for reduction of ammonia levels as well as liver transplantation as a definitive therapy.