[Distribution of cystinuria subtypes in the Democratic Republic of Germany]

The classic cystinuria is a hereditary disorder characterized by a defective transport of cystine and the dibasic amino acids arginine, lysine and ornithine in the epithelial cells of the renale tubule and the gastrointestinal tract. The excretion patterns of cystine and the dibasic amino acids in 24-hour urine samples from heterozygotes can be used to the differentiation between the genetic subtypes. 120 probands in the age range from 3 to 70 years from 22 families with cystinuria were investigated by thin-layer chromatography and by ion exchange chromatography. In patients with cystinuria the genotype I-I has a frequency of 50%. These results and the distribution of the other subtypes are in accordance with published data. From 98 persons investigated in 22 families with cystinuria 14 run the risk to form cystine stones. Therefore, the knowledge of the subtypes is relevant for practice.