GATM and hyperinsulinemic hypoglycemia, familial, 4: This includes kidney and thyroid dysfunctions, neurological diseases and post-traumatic GAA deficit, along with L-arginine:glycine amidinotransferase deficiency, ornithine aminotransferase deficiency and urea cycle disorders; we also put forward criteria for normal and abnormal GAA levels, and clinical features of GAA deficiency.