Cystinuria is characterized by defective reabsorption of four dibasic amino-acids, cystine, arginine, ornithine, and lysine by the proximal renal tubules and enterocytes. It contributes about 1-2% of renal lithiases overall and 6-8% of renal lithiases in pediatric patients. Three types of cystinuria are classically differentiated, based on urinary excretion of the four amino- acids in heterozygotes and on their intestinal absorption in homozygotes. The rBAT gene on chromosome 2 has been shown to be responsible for the transport of dibasic and neutral amino-acids. Positive linkage has also been demonstrated between cystinuria and three markers on the short arm of chromosome 2. Mutations of the rBAT gene have been demonstrated only in Type I cystinuria, indicating that cystinuria is genetically heterogeneous. A study of seven families is reported. Two families had two affected siblings each. All 14 patients were heterozygous for the disease. The cystinuria was I/I in four families, I/II in one family, and III/III in two families. Four different mutations were found. All occurred in patients with type I disease. To date, there is no evidence that the severity of cystinuria is correlated with the type of mutation.
|Number of pages||4|
|Journal||Annales de Pediatrie|
|Publication status||Published - 1997|
- Gene mutations
ASJC Scopus subject areas
- Pediatrics, Perinatology, and Child Health