In the urea cycle, six enzymes are required to convert ammonia to urea: N-acetylglutamate synthetase (NAGS), carbamoylphosphate synthetase (CPS), ornithine transcarbamylase (OTC), argininosuccinate synthetase (ASS), argininosuccinate lyase, and arginase. Deficiency of any of these enzymes may cause disease. Such infants are asymptomatic for 1–5 days but then feed poorly, vomit, and become lethargic. They may be irritable, rigid, and convulse. They exhibit hyperpnea and respiratory alkalosis, hepatomegaly, and jaundice; and they may have brain edema with bulging fontanels. Death ensues without treatment.
KeywordsUrea Cycle Respiratory Alkalosis Glutaric Aciduria Type Carbamoylphosphate Synthetase Ornithine Transcarbamylase
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12 Urea Cycle Disorders
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