Arginase deficiency presenting as acute encephalopathy

Urea cycle disorders are rare metabolic disorders that present as encephalopathy with hyperammonemia. Arginase deficiency causing hyperargininemia is one among the urea cycle disorders, which usually presents as spastic diplegia. Hyperammonemic encephalopathy is rare in arginase deficiency. We present a rare case of arginase deficiency presenting as acute encephalopathy in a child.