Patients. We studied 57 cystinuria patients from 45 families with the following ethnic origin: Macedonian (five), Serbian (nine), Albanian (nine), Gypsy (eight), Turkish (nine), Croatian (two), Montenegrin (two) and Egyptian (one). Informed consent was obtained from all patients.In this study we present five families in which novel mutations were found.

We studied 57 cystinuria patients from 45 families with the following ethnic origin: Macedonian (five), Serbian (nine), Albanian (nine), Gypsy (eight), Turkish (nine), Croatian (two), Montenegrin (two) and Egyptian (one). Informed consent was obtained from all patients.In this study we present five families in which novel mutations were found.

Patient CY-3 is of Macedonian origin and was examined as a 9-month-old baby. He had a 12 mm calculus in the left kidney, which subsequently caused obstruction and the patient underwent pielolithotomy.

Patients CY-8, CY-13 and CY-15 are of Serbian ethnic origin. Patient CY-8 was diagnosed with cystinuria when she was 2 years old. She has had several calculosis and one surgery.

Patient CY-13 experienced his first episode of urolithiasis at the age of 2 years. Due to recurrent urolithiasis, he underwent surgery, and has received extracorporeal shock wave lithotripsy several times.

Patient CY-15 was diagnosed with a calculi in the left kidney when he was 1-year-old. Since then he has undergone two surgeries due to urolithiasis.

Patient CY-36 is of Turkish ethnic origin. Ultrasonographic analysis of the kidneys showed a minimal pelvi-calexeal dilatation and lithiasis of the right kidney.

Methods. The diagnosis of cystinuric patients was based on positive sodium nitroprusside test and amino acid analysis (Beckman 6300 Amino Acid Analyzer; Beckman Coulter Inc., Fullerton, CA, USA). The patients were classified on the basis of their and their parent’s urinary cystine and dibasic amino acid excretion [8]. Genomic DNA was isolated from peripheral blood using Proteinase K-SDS digestion, followed by phenol-chloroform extraction, and ethanol precipitation.

Genomic DNA from all patients was amplified by polymerase chain reaction (PCR), using intron-derived oligonucleotides for each exon in the SLC7A9 [11] and SLC3A1 genes [12]. The mutational screening of the probands was performed by direct sequencing on an ABI PRISM™ 310 Genetic Analyzer (Applied Biosystems, Foster City, CA, USA) with BigDye^TM Terminator Cycle Sequencing Ready Reaction Kit (Applied Biosystems) and the primers used for PCR. Mutations in the family members were detected with PCR analyses followed by single strand conformational polymorphism (SSCP) (C242R, G73R), restriction fragment length polymorphism (RFLP) (MseI for V375I, ApaI for G105R) and heteroduplex analysis (1048-1051 delACTC).