However, the characteristic biochemical features of each CCDD is unique: elevated guanidinoacetate in body fluids in GAMT deficiency, low or low normal urine guanidinoacetate and low plasma guanidinoacetate in AGAT deficiency and elevated urine creatine in CRTR deficiency in males. This evidence concerns the gene GAMT and hyperinsulinemic hypoglycemia, familial, 4.