A RARELY SEEN UREA CYCLE DEFECT: CITRULINEMIA

Sonmez OE¹, Hatipoglu S¹, Cetin BD², Aksu K¹

¹ Department of Pediatrics

² Department of Clinical Microbiology and Infectious Diseases

Sisli Etfal Training and Research Hospital, Istanbul, Turkey

The free ammonia produced by the catabolism of aminoacids is detoxifed to urea through reactions that are catalyzed by urea cycle enzymes the affected children usually become symptomatic with vomiting, tachypnea, lehtargy progressing to a deep coma and convulsions after a few days of protein feeding. A 18-months old female patient was hospitalized in our department with clinical manifestations of vomiting, ataxia, mental confusions, agitation, irritability and combativeness. She had a sister who had died in neonatal period and undiagnosed. Her father and mother were cousins. Physical examination revealed lethargy, somnolence progressing to coma. Bileteral light reflexes were positive, pupils were isocoric. There were no meningeal irritation signs. She had hepatomegaly. Laboratory studies showed AST: 476 IU/L ALT: 1763 IU/L LDH: 1085 U/L ALP: 1020 U/L, PT: 20 sec. PTT: 40 sec., Protrombin activity: %50, BUN: 5 mg/dL. Serum concentration of bicarbonate and pH were normal. Hepatic markers were negative. Plasma ammonia nitrogen levels were high (400 mmol/l). Lumbar puncture results revealed no cell in CSF, normal biochemical findings and culture remained sterile. No spesific finding in urine analysis were found. While searching plasma aminoacid levels plasma citrulline levels were found high. (500 mmol/L). The clinical symptoms of our breast feeding infant were in silence in subacute citrullinemia. After begining the diet that contains higher protein, she had vigorous clinical progress a hyperammonemia that needs urgent diagnosis and therapy. In differentiating major causes of metabolic encephalopathy, especially if there is a history of death in the neonatal period in the family (inherited autosomal recessive trait), diagnosis of urea cycle defects that require urgent spesific laboratory studies should be investigated.

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