A study of the renal handling and intestinal absorption of dibasic amino acids in a patient with genotype +/11 heterozygous cystinuria and idiopathic hypercalcuria

A case is reported of a patient with idiopathic hypercalcuria who was referred for investigation of renal calculi. Studies of urinary amino acid excretion in the patient and all living members of his family, as well as studies of endogenous renal clearances of dibasic amino acids and cystine in the patient and his daughter, indicated that the patient had genotype +/11 heterozygous cystinuria. Intestinal perfusion studies showed however that the patient was able to absorb l-lysine, l-arginine normally from the jejunum and ileum. This suggests that a difference exists between renal and intestinal handling of lysine and arginine in cystinuria.