Clinical characteristics and analysis of mass spectrometric data in patients with ornithine transcarbamylase deficiency

Abstract

To explore the clinical manifestations and biochemical characteristics of patients with ornithine transcarbamylase deficiency (OTCD) so as to increase the clinician awareness for this disease. The clinical manifestations, blood ammonia levels, citrulline levels, urinary orotic acid and uracil levels were analyzed for 40 patients with OTCD from 2005 to 2013. And comparisons were made with 25 healthy children. Among them, the median age of onset was 1.4 years (3 days-29 years). The major clinical manifestations were feeding difficulties, persistent vomiting, convulsions, unconsciousness and hyperammonemia, etc. The blood levels of citrulline in these patients were significantly lower than those of the control group (6.35 (1.84-21.11) vs 13.65 (10.23-24.52) µmol/L, P < 0.05) . The urinary levels of orotic acid and uracil in these patients were significantly higher than those in the control group (167.77 (1.21-1 650.45) vs 0.25 (0-2.32) mmol/molCr, 52.67 (3.50-338.64) vs 0.69 (0-2.87) mmol/molCr, P < 0.05) . For patients with hyperammonemia, the decreased levels of citrulline in blood tested by tandem mass spectrometry and increased orotic acid and uracil in urine on gas chromatography-mass spectrometry may aid the diagnosis OTCD.