Korean J Pediatr.  2016 Nov;59(Suppl 1):S103-S106. 10.3345/kjp.2016.59.11.S103.

A novel mutation of CLCNKB in a Korean patient of mixed phenotype of Bartter-Gitelman syndrome

• Cho HW
• Lee ST
• Cho H
• Cheong HI

• KMID: 2362268
• DOI: http://doi.org/10.3345/kjp.2016.59.11.S103

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.

Keyword

Bartter Syndrome; Novel mutation; CLCNKB

MeSH Terms

Alkalosis
Bartter Syndrome
Blood Pressure
Child
Computer Simulation
Exons
Gitelman Syndrome
Humans
Hyperaldosteronism
Hypokalemia
Male
Muscle Cramp
Nephrocalcinosis
Phenotype*