A novel mutation of CLCNKB in a Japanese patient of Gitelman-like phenotype with diuretic insensitivity to thiazide administration.
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ABSTRACT:
SUBMITTER: Ohkubo K
PROVIDER: S-EPMC4287957 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description: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.
| S-EPMC5177689 | biostudies-literature
Project description:Patients with renal diseases associated with salt-losing tubulopathies categorized as Gitelman and classic form of Bartter syndrome have undergone genetic screening for possible mutation capture in two different genes: SLC12A3 and CLCNKB. Clinical symptoms of these two diseases may overlap. Bartter syndrome and Gitelman syndrome are autosomal recessive salt-losing tubulopathies with hypokalemia, metabolic alkalosis, hyperreninemia, hyperplasia of the juxtaglomerular apparatus, hyperaldosteronism, and, in some patients, hypomagnesemia. Here we describe four patients from an inbred family with a novel missense variant in the CLCNKB gene. All of patients are asymptomatic; yet they have the typical metabolic abnormality of salt losing tubulopathies. One of those patients had hypomagnesaemia while others not. Clinical and laboratory data of all patients was described. All 4 patients have a homozygous c.490G > T missense variant in exon 5 of the CLCNKB gene. This variant alters a glycine into a cysteine on amino acid position 164 of the resulting protein (p.Gly164Cys). The c.490G > T variant is a novel variant not previously described in other patients nor controls. Polyphen analysis predicts the variation to be possibly damaging. Analysis of SLC12A3 was normal. Here in we are describing a novel homozygous c.490G > T missense variation was identified in exon 5 of the CLCNKB gene was identified in an Emirati patients with a mild manifestation of Bartter - Gitelman syndrome.
| S-EPMC3977018 | biostudies-literature
Project description:The purpose of this study was to evaluate the reasons physicians provided when the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC 7) guidelines recommending a thiazide diuretic as a first line treatment for hypertension were not followed. A subsample of patients from a randomized controlled study who had uncontrolled blood pressure at an index visit and were not prescribed a thiazide were evaluated. Differences in groups that received any medication change or therapeutic lifestyle changes counseling and those that did not were compared. Differences in treatment were also compared for patients who received educational materials with or without telephone calls and financial incentive with a control group. The authors examined whether patients achieved blood pressure control in 12 months. The results show providers are not aggressive enough with getting blood pressure to goal and patients who are more educated about hypertension may be less likely to experience clinical inertia.
| S-EPMC8673042 | biostudies-literature
Project description:Background:Gitelman syndrome (GS) is considered as the most common renal tubular disorder, and we report the first Romanian patient with GS confirmed at molecular level and diagnosed according to genetic testing. Patient and methods:This paper describes the case of a 27-year-old woman admitted with severe hypokalemia, slight hypomagnesemia, hypocalcemia, hypocalciuria, metabolic alkalosis, hyperreninemia, low blood pressure, limb muscle weakness, marked fatigue and palpitations. Family history revealed a consanguineous family with autosomal-recessive transmission of GS with two cases over five generations. Results:Next-generation sequencing technology detected two different homozygous mutations c.1805_1806delAT and c.2660+1G>A in the SLC12A3 gene, which encodes the thiazide-sensitive NaCl co-transporter, confirmed by the Sanger method. Conclusion:Clinicians should be aware of the existence of GS, manage the condition properly and consider the risk of disease recurrence to the next generations.
| S-EPMC5784745 | biostudies-literature
Project description:BackgroundGitelman syndrome (GS) is an autosomal recessive disorder and mild variant of classic Bartter syndrome. The latter is caused by defects in the genes CLCNKB and/or CLCNKA (chloride voltage-gated channel Ka and Kb). Patients with GS usually have loss-of-function mutations in SLC12A3. No patient has been reported with compound heterozygous mutations in these genes. We report a girl with GS with a paternally inherited heterozygous mutation in SLC12A3, and maternally inherited heterozygous variants in both CLCNKB and CLCNKA.Case presentationIn this report, we reported a female patient (8 y and 10 mo) who had growth retardation (111.8 cm, - 1.62 standard deviation height for age) and normal blood pressure, with persistent hypokalemia, hypomagnesemia, hypocalciuria, hypochloremic alkalosis, and elevated levels of plasma renin and aldosterone. Her younger brother, father, and paternal grandmother all had histories of mild low levels of plasma potassium (3.0-3.5 mmol/L), which were rectified by potassium-rich foods. The genomic DNA of the patient, younger brother, parents, and grandparents were screened for gene variations and pedigree analysis using trio whole exome sequencing (WES). The candidate variants were validated by Sanger sequencing. Protein-protein interaction analysis utilized the following databases: Biogrid, MINT, HPRD, STRING, IntAct, iRefIndex, and ppiTrim. The trio WES screening showed that the patient has paternally inherited SLC12A3 p.N359K, and maternally inherited CLCNKB p.L94I. The paternal grandmother and younger brother are both carriers of SLC12A3 p.N359K. According to the STRING database, SLC12A3 and CLCNKB proteins may interact or coexpress with proteins associated with GS.ConclusionsBased on clinical phenotypes, genetic evidence of the pedigree, and previous reported studies, this case of GS indicates a digenetic inheritance of SLC12A3 and CLCNKB that resulted in renal tubular dysfunction perhaps, due to a genetic double-hit mechanism. The putative pathogenicity of the CLCNKB p.L94I variant requires confirmation.
| S-EPMC6471809 | biostudies-literature
Project description:AimsThiazide diuretics are recommended as first line antihypertensive treatment, but may contribute to new onset diabetes. We aimed to describe change in fasting glucose (FG) during prolonged thiazide treatment in an observational setting.MethodsWe conducted an observational, non-randomized, open label, follow-up study of the Pharmacogenomic Evaluation of Antihypertensive Responses (PEAR) and PEAR-2 studies. We enrolled previous participants from the PEAR or PEAR-2 studies with at least 6 months of continuous treatment with either hydrochlorothiazide (HCTZ) or chlorthalidone. Linear regression was used to identify associations with changes in FG after prolonged thiazide and thiazide-like diuretic treatment.ResultsA total of 40 participants were included with a mean 29 (range 8-72) months of thiazide treatment. FG increased 6.5 (SD 13.0) mg/dL during short-term thiazide treatment and 3.6 (SD 15.3) mg/dL FG during prolonged thiazide treatment. Increased FG at follow-up was associated with longer thiazide treatment duration (β=0.34, p=0.008) and lower baseline FG (β=-0.46, p=0.02). β blocker treatment in combination with prolonged thiazide diuretic treatment was also associated with increased FG and increased 2-h glucose obtained from OGTT.ConclusionsOur results indicate that prolonged thiazide treatment duration is associated with increased FG and that overall glycemic status worsens when thiazide/thiazide-like diuretics are combined with β blockers.
| S-EPMC4074403 | biostudies-literature
Project description:We conducted a genome-wide association study to identify novel genes influencing diastolic blood pressure (BP) response to hydrochlorothiazide, a commonly prescribed thiazide diuretic preferred for the treatment of high BP. Affymetrix GeneChip Human Mapping 100K Arrays were used to measure single nucleotide polymorphisms across the 22 autosomes in 194 non-Hispanic black subjects and 195 non-Hispanic white subjects with essential hypertension selected from opposite tertiles of the race- and sex-specific distributions of age-adjusted diastolic BP response to hydrochlorothiazide (25 mg daily, PO, for 4 weeks). The black sample consisted of 97 "good" responders (diastolic BP response [mean+/-SD]=-18.3+/-4.2 mm Hg; age=47.1+/-6.1 years; 51.5% women) and 97 "poor" responders (diastolic BP response=-0.18+/-4.3; age=47.4+/-6.5 years; 51.5% women). Haplotype trend regression identified a region of chromosome 12q15 in which haplotypes constructed from 3 successive single nucleotide polymorphisms (rs317689, rs315135, and rs7297610) in proximity to lysozyme (LYZ), YEATS domain containing 4 (YEATS4), and fibroblast growth receptor substrate 2 (FRS2) were significantly associated with diastolic BP response (nominal P=2.39 x 10(-7); Bonferroni corrected P=0.024; simulated experiment-wise P=0.040). Genotyping of 35 additional single nucleotide polymorphisms selected to "tag" linkage disequilibrium blocks in these genes provided corroboration that variation in LYZ and YEATS4 was associated with diastolic BP response in a statistically independent data set of 291 black subjects and in the sample of 294 white subjects. These results support the use of genome-wide association analyses to identify novel genes influencing antihypertensive drug responses.
| S-EPMC2692710 | biostudies-literature
Project description:Gitelman syndrome is a rare, recessively inherited disease characterized by chronic hypokalemia and hypomagnesemia as a result of defective electrolyte co-transport at the level of the distal convoluted tubule of the kidney. Here, we present the first report of a patient with Gitelman syndrome who developed multiple neoplasia including colorectal polyposis, synchronous colorectal cancers, recurrent breast fibroadenomata and a desmoid tumor. Whole-exome sequencing confirmed germline compound heterozygous mutations of c.179C > T and c.1326C > G in SLC12A3, and in addition, identified a monoallelic germline c.934-2A > G splice site mutation in MUTYH. In vitro, magnesium deficiency potentiated oxidative DNA damage in lymphoblastoid cell lines derived from the same patient. We postulate that monoallelic MUTYH mutations may manifest in the presence of cooperative non-genetic mechanisms, in this case possibly magnesium deficiency from Gitelman syndrome.
| S-EPMC7501863 | biostudies-literature
Project description:BackgroundPrior meta-analyses measuring thiazide-induced glycemic change have demonstrated an increased risk of incident diabetes; however, this measure's definition has changed over time.AimTo determine the magnitude of change in fasting plasma glucose (FPG) for thiazide diuretics.Data sourcesA research librarian designed and conducted searches in Medline®, EMBASE, and EBM Reviews-Cochrane Central Register of Controlled Trials (inception through July 2018) and International Pharmaceutical Abstracts (inception to December 2014).Study selectionRandomized, controlled trials comparing a thiazide or thiazide-like diuretic to any comparator reporting FPG were identified. Trials enrolling < 50 participants, those with a follow-up period of < 4 weeks, and conference abstracts were excluded.Data extractionIndependent duplicate screening of citations and full-text articles, data extraction, and assessment of risk of bias was conducted.Data synthesisNinety-five studies were included (N = 76,608 participants), with thiazides compared with placebo, beta-blockers, calcium channel blockers, renin-angiotensin-aldosterone-system inhibitors, potassium-sparing diuretic, and others alone or in combination. Thiazide diuretics marginally increased FPG (weighted mean difference 0.20 mmol/L (95% CI 0.15-0.25); I2 = 84%) (1 mmol/L = 18 mg/dL). Results did not change substantially when considering dose or duration, comparing thiazides with placebo or an active comparator, or using thiazides as monotherapy or combination therapy, even when combined with a potassium-correcting agent.ConclusionThiazide diuretics have a small and clinically unimportant impact on FPG.
| S-EPMC7280437 | biostudies-literature
Project description:BackgroundThiazide diuretics are commonly prescribed to prevent kidney stones. However, it is unclear whether higher doses confer greater benefit.ObjectiveTo determine whether lower doses of thiazide diuretics confer a similar protective effect against kidney stone events as higher doses.DesignPopulation-based cohort study.SettingLinked health administrative databases in Ontario, Canada.PatientsOlder adults newly prescribed a thiazide diuretic between 2003 and 2014 were separated into 2 groups based on daily dose: low dose (⩽12.5 mg hydrochlorothiazide/chlorthalidone, or ⩽1.25 mg indapamide) or high dose.MeasurementsThe primary outcome was time to a kidney stone event, using diagnosis and procedure codes. A secondary outcome was kidney stone surgery.MethodsAn association between thiazide diuretic dose and a kidney stone event was estimated using Cox proportional hazards regression.ResultsA total of 536 of 105 239 patients (0.51%) experienced a kidney stone event. We did not detect a difference in kidney stone risk in the high-dose relative to the low-dose group (adjusted hazard ratio, 1.10; 95% confidence interval, 0.93-1.31). Results were similar when analysis was restricted to the more specific outcome of kidney stone surgery. Neither a history of prior kidney stones nor the type of thiazide diuretic modified the effect of diuretic dose on outcome.LimitationsPatients were >65 years old and we were unable to adjust for some potential confounders such as dietary factors.ConclusionsLower dose thiazide diuretics appear to confer a similar protective effect as higher dose thiazides against the development of kidney stones.
| S-EPMC6048667 | biostudies-literature