Abstract
The authors report the case of a 20-year-old man with unexplained hypokalemia and metabolic alkalosis suggesting hypokalemic tubulopathy. Interestingly, he showed a mixed phenotype of Gitelman's syndrome (GS) and Bartter's syndrome, which includes normomagnesemia, normal renal magnesium excretion, and hypocalciuria. Renal clearance study showed the presence of a critical defect in the distal nephron rather than loop of Henle. Further family study showed that his mother had a definitive phenotype of GS. By the molecular genetic analysis of these patients, 7 different mutations of the NCCT gene were identified consisting of 3 missense, 1 splice site, and 3 silent mutations. Four of these mutations were novel. The authors emphasize that the combination of a molecular genetic approach and renal clearance study could be of practical benefit in confusing clinical setting and support new diagnostic criteria in GS.
MeSH terms
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Adult
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Alkalosis / genetics
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Amino Acid Substitution
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Bartter Syndrome / diagnosis
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Bartter Syndrome / genetics
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Calcium / urine
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Carrier Proteins / chemistry
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Carrier Proteins / genetics*
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DNA Mutational Analysis
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Diagnosis, Differential
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Exons / genetics
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Female
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Humans
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Hypokalemia / genetics
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Hypokalemic Periodic Paralysis / genetics*
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Introns / genetics
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Korea
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Magnesium / blood
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Male
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Mutagenesis, Insertional
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Mutation*
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Mutation, Missense
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Phenotype
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RNA Splice Sites / genetics
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Receptors, Drug*
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Renal Tubular Transport, Inborn Errors / diagnosis
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Renal Tubular Transport, Inborn Errors / genetics*
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Renal Tubular Transport, Inborn Errors / metabolism
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Sodium Chloride Symporters
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Solute Carrier Family 12, Member 3
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Symporters*
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Syndrome
Substances
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Carrier Proteins
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RNA Splice Sites
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Receptors, Drug
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SLC12A3 protein, human
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Sodium Chloride Symporters
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Solute Carrier Family 12, Member 3
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Symporters
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thiazide receptor
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Magnesium
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Calcium