Arginase Deficiency

Excerpt

Arginase deficiency (argininemia) is an autosomal recessive metabolic disorder characterized by hyperammonemia secondary to arginine accumulation. Ammonia levels can vary according to the patient’s current age and status, presenting initially with slow growth, followed by developmental delay and cognitive problems. When improperly treated, it may lead to regression.

Often diagnosed at birth through newborn screening (NBS), affected newborns are found to have elevated levels (up to 4 times) of arginine. Its management is similar to other classic urea cycle disorders, although with mild or absent hyperammonemia. If hyperammonemia is present, it responds adequately to ammonia-reducing interventions. Chronic treatment consists of protein restriction along with nitrogen-scavenging medications.