Bartter syndrome with long-term follow-up: a case report

Bartter Syndrome: A Systematic Review of Case Reports and Case Series

Background and Objectives: Bartter syndrome (BS) is a rare group of autosomal-recessive disorders that usually presents with hypokalemic metabolic alkalosis, occasionally with hyponatremia and hypochloremia. The clinical presentation of BS is heterogeneous, with a wide variety of genetic variants. The aim of this systematic review was to examine the available literature and provide an overview of the case reports and case series on BS. Materials and Methods: Case reports/series published from April 2012 to April 2022 were searched through Pubmed, JSTOR, Cochrane, ScienceDirect, and DOAJ. Subsequently, the information was extracted in order to characterize the clinical presentation, laboratory results, treatment options, and follow-up of the patients with BS. Results: Overall, 118 patients, 48 case reports, and 9 case series (n = 70) were identified. Out of these, the majority of patients were male (n = 68). A total of 21 patients were born from consanguineous marriages. Most cases were reported from Asia (73.72%) and Europe (15.25%). In total, 100 BS patients displayed the genetic variants, with most of these being reported as Type III (n = 59), followed by Type II (n = 19), Type I (n = 14), Type IV (n = 7), and only 1 as Type V. The most common symptoms included polyuria, polydipsia, vomiting, and dehydration. Some of the commonly used treatments were indomethacin, potassium chloride supplements, and spironolactone. The length of the follow-up time varied from 1 month to 14 years. Conclusions: Our systematic review was able to summarize the clinical characteristics, presentation, and treatment plans of BS patients. The findings from this review can be effectively applied in the diagnosis and patient management of individuals with BS, rendering it a valuable resource for nephrologists in their routine clinical practice.

A Rare Presentation of Adult-Onset Bartter Syndrome: A Case Report

Bartter syndrome is a rare, salt-wasting tubulopathy with impaired ion reabsorption in the ascending limb of the loop of Henle, which results in hypokalemia, hypochloremia, and hypercalciuria. It usually presents in neonates, with vomiting, dehydration, and failure to thrive. It results from mutations in several genes, including KCNJ1, CLCNKB, CLCNKA, BSND, and ROMK, which encode ion transporters. We report a rare presentation of adult-onset Bartter syndrome. In this case, a 27-year-old man presented to the hospital with upper and lower limb weakness. Bartter syndrome was suspected based on serum electrolytes assessment and arterial blood gas analysis. The patient was initiated on potassium chloride (KCL) infusion and potassium chloride syrup to correct hypokalemia.

A novel CLCNKB variant in a Chinese family with classic Bartter syndrome and prenatal genetic diagnosis

Background

Type III Bartter syndrome (BS), often known as classic Bartter syndrome is caused by variants in CLCNKB gene, which encoding the basolateral chloride channel protein ClC‐Kb, and is characterized by renal salt wasting, hypokalemia, metabolic alkalosis, increased renin, and aldosterone levels.

Methods

A 2‐year‐old boy presented severe malnutrition, severe metabolic alkalosis and severe hypokalemia and was clinically diagnosed with BS. The trio exome sequencing (ES) was performed to discover the genetic cause of this patient, followed by validation using Sanger sequencing and quantitative polymerase chain reaction subsequently.

Results

The genetic analysis indicated that this patient with a compound heterozygous variants of CLCNKB gene including a novel nonsense variant c.876 T > A and a whole‐gene deletion. The two variants were inherited from his parents, respectively. Subsequently, target sequencing of CLCNKB gene was performed for next pregnancy, and prenatal genetic diagnosis was provided for the family.

Conclusions

The results of current study identified the compound heterozygous variants in a patient with classic BS. The novel variant expands the spectrum of CLCNKB variants in BS. Our study also indicates that ES is an alternative tool to simultaneously detect single‐nucleotide variants and copy‐number variants.