Clinical and Experimental Pediatrics

The Korean Pediatric Society (대한소아청소년과학회)
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A novel mutation of CLCNKB in a Korean patient of mixed phenotype of Bartter-Gitelman syndrome

  • Cho, Hee-Won (Department of Pediatrics, Samsung Medical Center, Sungkyunkwan University School of Medicine) ;
  • Lee, Sang Taek (Department of Pediatrics, Samsung Medical Center, Sungkyunkwan University School of Medicine) ;
  • Cho, Heeyeon (Department of Pediatrics, Samsung Medical Center, Sungkyunkwan University School of Medicine) ;
  • Cheong, Hae Il (Department of Pediatrics, Seoul National University Children's Hospital)
  • Received : 2015.11.25
  • Accepted : 2016.01.27
  • Published : 2016.11.15
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Abstract

Bartter syndrome (BS) is an inherited renal tubular disorder characterized by low or normal blood pressure, hypokalemic metabolic alkalosis, and hyperreninemic hyperaldosteronism. Type III BS is caused by loss-of-function mutations in CLCNKB encoding basolateral ClC-Kb. The clinical phenotype of patients with CLCNKB mutations has been known to be highly variable, and cases that are difficult to categorize as type III BS or other hereditary tubulopathies, such as Gitelman syndrome, have been rarely reported. We report a case of a 10-year-old Korean boy with atypical clinical findings caused by a novel CLCNKB mutation. The boy showed intermittent muscle cramps with laboratory findings of hypokalemia, severe hypomagnesemia, and nephrocalcinosis. These findings were not fully compatible with those observed in cases of BS or Gitelman syndrome. The CLCNKB mutation analysis revealed a heterozygous c.139G>A transition in exon 13 [p.Gly(GGG)465Glu(GAG)]. This change is not a known mutation; however, the clinical findings and in silico prediction results indicated that it is the underlying cause of his presentation.

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References

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