CLCNKB and Bartter syndrome: Next-generation sequencing identified <i>CLCNKB</i> gene mutation including heterozygous mutation c.1257delC (p.M421Cfs*58) and a low-level mutation c.595G > T (p.E199*); both mutations were also verified in the parents.<h4>Conclusion</h4>We reported the case of a classic Bartter syndrome in a newborn with a heterozygous frameshift mutation and a mosaic non-sense mutation in the <i>CLCNKB</i> gene.