From OMIM
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. Urea cycle disorders 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 (311250), carbamyl phosphate synthetase deficiency (237300), argininosuccinate synthetase deficiency, or citrullinemia (215700), argininosuccinate lyase deficiency (207900), and arginase deficiency.  http://www.omim.org/entry/207800

From MedlinePlus Genetics
Arginase deficiency is an inherited disorder that causes the amino acid arginine (a building block of proteins) and ammonia to accumulate gradually in the blood. Ammonia, which is formed when proteins are broken down in the body, is toxic if levels become too high. The nervous system is especially sensitive to the effects of excess ammonia.

Arginase deficiency usually becomes evident by about the age of 3. It most often appears as stiffness, especially in the legs, caused by abnormal tensing of the muscles (spasticity). Other symptoms may include slower than normal growth, developmental delays and eventual loss of developmental milestones, intellectual disabilities, seizures, tremors, and difficulty with balance and coordination (ataxia). Occasionally, high-protein meals or stress caused by illness or periods without food (fasting) may cause ammonia to accumulate more quickly in the blood. This rapid increase in ammonia may lead to episodes of irritability, refusal to eat, and vomiting.

In some affected individuals, the signs and symptoms of arginase deficiency may be less severe and may not appear until later in life.  https://medlineplus.gov/genetics/condition/arginase-deficiency