Definition: Arginase deficiency is an autosomal recessive inborn error of metabolism caused by a defect in the final step in the urea cycle, the hydrolysis of arginine to urea and ornithine.
Etiology
argininemia is caused by mutation in the gene encoding liver arginase (ARG1) (MIM.608313).
Nota bene`: Urea cycle diseases are characterized by the triad of hyperammonemia, encephalopathy, and respiratory alkalosis. Five disorders involving different defects in the biosynthesis of the enzymes of the urea cycle have been described: ornithine transcarbamylase deficiency (MIM.311250), carbamyl phosphate synthetase deficiency (MIM.237300), argininosuccinate synthetase deficiency, or citrullinemia (MIM.215700), argininosuccinate lyase deficiency (MIM.207900), and arginase deficiency.