arginase deficiency

Pathology: - urea cycle disorder - arginase mediates terminal step in urea cycle Genetics: - autosomal recessive - defect in arginase-1 Clinical manifestations: - typical presentation as older infant - delayed development - protein intolerance - occasional episodes of vomiting & somnolence without apparent cause - spastic diplegia Laboratory: - plasma ammonia: hyperammonemia is rarely observed - urine arginine generally not massive - serum arginine may not be greatly increased with restriction of protein intake Differential diagnosis: - argininosuccinate lyase deficiency - methylmalonic acidemia - carbamoyl phosphate synthetase deficiency - N-Acetylglutamate synthetase deficiency - citrullinemia - ornithine transcarbamylase deficiency - hyperammonemia - propionic acidemia (propionyl CoA carboxylase deficiency) - hyperammonemia-hyperornithinemia-homocitrullinemia syndrome - hyperinsulinemia - cerebral palsy Management: - low protein diet - oral sodium benzoate or sodium phenylbutyrate - consults a) medical geneticist b) metabolic disease specialist c) dietitian

References

-Roth KS Arginase Deficiency eMedicine http://emedicine.medscape.com/article/941838-overview