Abstract: Objective To explore the clinical characteristics of Bartter syndrome(BS)in children and analyze the characteristics of CLCNKB gene mutation. Methods The clinical data of two unrelated BS family probands and their family members were analyzed. The peripheral blood DNA was extracted with column method. Primers were designed for the coding region of exons of BS-related mutant genes and then amplified. The PCR products were sequenced and compared with the normal sequences in NCBI by BLAST to identify possible gene mutations. Large fragment deletions were detected with multiple ligation probe amplification technique. Results Laboratory tests of both probands showed hypokalemia, alkalosis, hyperreninemia and hyperaldosteroneemia. Large fragment homozygous deletions of exons 1-3, 5-6, 8, 10-11, 13-15 and 17-19 of CLCNKB were detected in pedigree 1, which were inherited from parents. Large fragment deletions of exons 1-3, 5-6, 8, 10-11, 13-15 and 17-19 of CLCNKB and c.1881delC(p.Thr628fs)compound heterozygous mutation were identified in pedigree 2, which were inherited from parents. Conclusion c.1881delC(p.Thr628fs)is a frameshift mutation, which has not been reported at home and abroad. CLCNKB gene mutation is the cause of the two BS families, and the diagnosis is type III classic BS. BS can be clinically identified with molecular genetics to improve the diagnosis rate and to implement timely treatment.

Key words: Bartter syndrome, CLCNKB gene, Gene mutation, Genotype