ARG1 and hyperinsulinemic hypoglycemia, familial, 4: However, the blood ammonia levels in our cases 1 and 4 at the time of onset were significantly high, and the blood ammonia levels in cases 2, 3, and 5 were moderately high, suggesting that the blood ammonia levels at the onset time could not distinguish patients with ARG1 deficiency from patients with other UCDs.