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Journal Article 
Congenital lysine intolerance with periodic ammonia intoxication 
Colombo, JP; Richterich, R; Donath, A; Spahr, A; Rossi, E 
The Lancet
ISSN: 0140-6736
EISSN: 1474-547X 
AMMONIA intoxication is occasionally seen in children with acquired severe liver disease. It has been demonstrated in congenital citrullinuria (McMurray et al. 1963), and in another disease entity possibly due to an enzyme defect in the urea cycle (Russell et al. 1962). We have encountered a 3-month-old girl who has had vomiting and episodes of coma since birth. During these comatose states, abnormally high concentrations of blood ammonia were found, The rises in ammonia and urea-nitrogen levels in the blood were directly proportional to the protein intake. On a low-protein diet (1-0-1-5 g. per kg. per day) the child remained well. An increase in protein to 2-5- 3-0 g. per kg. per day-the usual intake at this age-was immediately followed by deterioration; the child became comatose and showed considerable rigidity of the muscles. Chromatographic studies of plasma aminoacids during high-protein intake revealed a significant increase in the
concentration of lysine and arginine. Preliminary investigations suggest that the child might be incapable of degrading lysine. Since lysine is a potent competitive inhibitor of arginase (Hunter and Downs 1945), an accumulation of this aminoacid possibly interferes with urea synthesis and ammonia detoxication, leading to an increase in ammonia levels and to ammonia intoxication.