OBJECTIVE: To explore the clinical characteristics and genetic basis for three children with Congenital chlorine diarrhea (CCD). METHODS: Three children with CCD who attended the Affiliated Children's Hospital of Capital Pediatric Institute from June 2014 to August 2020 were selected as the research subjects. Peripheral blood samples of the three children and their parents were collected for genetic testing. And the results were verified by Sanger sequencing. RESULTS: The clinical manifestations of the three children have included recurrent diarrhea, with various degrees of hypochloremia, hypokalemia and refractory metabolic alkalosis. Genetic testing revealed that the three children have all carried variants of the SLC26A3 gene, including homozygous c.1631T>A (p.I544N) variants, c.2063_1G>T and c.1039G>A (p.A347T) compound heterozygous variants, and c.270_271insAA(p.G91kfs*3) and c.2063_1G>T compound heterozygous variants. Sanger sequencing confirmed that all of the variants were inherited from their parents. CONCLUSION The variants of the SLC26A3 gene probably underlay the CCD in these children. Above finding has enriched the spectrum of SLC26A3 gene variants.
Humans ; Child ; Chlorine ; Genetic Testing ; Hypokalemia/genetics* ; Homozygote ; Diarrhea/genetics* ; Mutation

OBJECTIVE: To explore the clinical features and genetic etiology of a patient with primary distal renal tubular acidosis (dRTA). METHODS: A child who was diagnosed with primary dRTA at the Xi'an Children's Hospital in April 2021 due to poor appetite and persistent crying was selected as the study subject. Clinical data of the patient was collected. Whole exome sequencing (WES) was carried out for the child. Candidate variants were validated by Sanger sequencing of his family members. RESULTS: The child, a 1-month-and-18-day male, had featured poor appetite, persistent crying, poor weight gain and dehydration. Laboratory examination has suggested metabolic acidosis, hyperchloremia, hypokalemia, abnormal alkaline urine and anemia. Ultrasonographic examination of the urinary system revealed calcium deposition in renal medulla. DNA sequencing revealed that he has harbored compound heterozygous variants of the ATP6V0A4 gene, namely c.1363dupA (p.M455NfsX14) and c.2257C>T (p.Q753X), which were respectively inherited from his father and mother. Based on the guidelines from the American College of Medical Genetics and Genomics, both variants were classified as pathogenic (PVS1+PM3+PM2_Supporting). CONCLUSION The compound heterozygous variants of c.1363dupA (p.M455NfsX14) and c.2257C>T (p.Q753X) of the ATP6V0A4 gene probably underlay the pathogenesis of primary dRTA in this patient. Discovery of the c.2257C>T (p.Q753X) variant has also expanded the mutational spectrum of the ATP6V0A4 gene.
Humans ; Male ; Acidosis, Renal Tubular/genetics* ; Family ; Genomics ; Hypokalemia ; Infant

OBJECTIVE: To report the clinical and genetic characteristics of a rare case of Gitelman syndrome with comorbid Graves disease and ACTH-independent adrenocortical adenoma. METHODS: A patient who had presented at the Nanchong Central Hospital on December 21, 2020 was selected as the study subject. Clinical data of the patient was collected. Whole-exome sequencing was carried out on DNA extracted from peripheral venous blood samples from the patient and her family members. RESULTS: The patient, a 45-year-old woman, was found to have Graves disease, ACTH-independent Cushing syndrome, hypokalemia and hypomagnesemia following the discovery of an adrenal incidentaloma. MRI scan had revealed a 3.8 cm × 3.2 cm mass in the left adrenal gland. The mass was removed by surgery and confirmed as adrenocortical adenoma. DNA sequencing revealed that the patient and her sister have both harbored compound heterozygous variants of the SLC12A3 gene, namely c.1444-10(IVS11)G>A and c.179(exon1)C>T (p.T60M), which were respectively inherited from their father and mother. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the c.1444-10(IVS11)G>A and c.179(exon1)C>T (p.T60M) were respectively classified as a variant of uncertain significance (PM2_Supporting+PP3) and a likely pathogenic variant (PM3_Strong+PM1+PP3). CONCLUSION The conjunction of Gitelman syndrome with Graves disease and adrenal cortex adenoma is rather rare. The newly discovered c.1444-10(IVS11)G>A variant of the SLC12A3 gene, together with the heterozygous variant of c.179(exon1)C>T (p.T60M), probably underlay the pathogenesis in this patient.
Humans ; Female ; Middle Aged ; Gitelman Syndrome/genetics* ; Adrenocortical Adenoma ; Hypokalemia ; Graves Disease/genetics* ; Mothers ; Mutation ; Solute Carrier Family 12, Member 3

Severe hypokalemia is defined as the concentration of serum potassium lower than 2.5 mmol/L, which may lead to serious arrhythmias and cause mortality. We report an unusual case of potentially fatal ventricular arrhythmias induced by severe hypokalemia in a patient undergoing laparoscopic partial nephrectomy in Peking University Third Hospital due to irregular use of indapamide before operation. Indapamide is a sulfonamide diuretic with vasodilative and calcium antagonistic effects, which enhances sodium delivery to the renal distal tubules resulting in a dose-related increase in urinary potassium excretion and decreases serum potassium concentrations. The electrolyte disorder caused by the diuretic is more likely to occur in the elderly patients, especially those with malnutrition or long-term fasting. Hence, the serum potassium concentration of the patients under indapamide therapy, especially elderly patients, should be monitored carefully. Meanwhile, the potassium concentration measured by arterial blood gas analysis is different from that measured by venous blood or laboratory test. According to the previous research, the concentration of potassium in venous blood was slightly higher than that in arterial blood, and the difference value was 0.1-0.5 mmol/L. This error should be taken into account when rapid intravenous potassium supplementation or reduction of blood potassium level was carried out clinically. In the correction of severe hypokalemia, the standard approach often did not work well for treating severe hypokalemia. The tailored rapid potassium supplementation strategy shortened the time of hypokalemia and was a safe and better treatment option to remedy life-threatening arrhythmias caused by severe hypokalemia with a high success rate. Through the anesthesia management of this case, we conclude that for the elderly patients who take indapamide or other potassium excretion diuretics, the electrolyte concentration and the general volume state of the patients should be comprehensively measured and fully evaluated before operation. It may be necessary for us to reexamine the serum electrolyte concentration before anesthesia induction on the morning of surgery in patients with the history of hypokalemia. For severe hypokalemia detected after anesthesia, central venous cannulation access for individualized rapid potassium supplementation is an effective approach to reverse the life-threatening arrhythmias caused by severe hypokalemia and ensure the safety of the patients.
Humans ; Aged ; Hypokalemia/complications* ; Indapamide/adverse effects* ; Arrhythmias, Cardiac/therapy* ; Diuretics/adverse effects* ; Potassium ; Electrolytes/adverse effects* ; Anesthesia, General/adverse effects*

BACKGROUND: The clinical importance of hypokalemia is likely underrecognized in Chinese dialysis patients, and whether its clinical effect was mediated by serum albumin is not fully elucidated. This study aimed to explore the association between serum potassium and mortality in dialysis patients of a Chinese nationwide multicenter cohort, taking albumin as a consideration. METHODS: This was a prospective nation-wide multicenter cohort study. Restricted cubic splines were used to test the linearity of serum potassium and relationships with all-cause (AC) and cardiovascular (CV) mortality and a subsequent two-line piecewise linear model was fitted to approach the nadir. A mediation analysis was performed to examine relations of albumin to potassium and mortalities. RESULTS: A total of 10,027 patients were included, of whom 6605 were peritoneal dialysis and 3422 were hemodialysis patients. In the overall population, the mean age was 51.7 ± 14.8 years, 55.3%(5546/10,027) were male, and the median dialysis vintage was 13.60 (4.70, 39.70) months. Baseline serum potassium was 4.30 ± 0.88 mmol/L. After a median follow-up period of 26.87 (14.77, 41.50) months, a U-shape was found between potassium and mortality, and a marked increase in risk at lower potassium but a moderate elevation in risk at higher potassium were observed. The nadir for AC mortality risk was estimated from piecewise linear models to be a potassium concentration of 4.0 mmol/L. Interestingly, the significance of the association between potassium and mortality was attenuated when albumin was introduced into the extended adjusted model. A subsequent significant mediation by albumin for potassium and AC and CV mortalities were found ( P < 0.001 for both), indicating that hypokalemia led to higher mortality mediated by low serum albumin, which was a surrogate of poor nutritional status and inflammation. CONCLUSIONS Associations between potassium and mortalities were U-shaped in the overall population. The nadir for AC mortality risk was at a potassium of 4.0 mmol/L. Serum albumin mediated the association between potassium and AC and CV mortalities.
Adult ; Aged ; Female ; Humans ; Male ; Middle Aged ; East Asian People ; Hypokalemia/etiology* ; Kidney Failure, Chronic/mortality* ; Potassium/blood* ; Prospective Studies ; Renal Dialysis ; Serum Albumin/analysis*

Introduction: Gitelman Syndrome (GS), a rare autosomal recessive inherited disorder, is frequently unrecognized in the clinical setting. GS typically manifests with severe hypokalemia with debilitating and potentially fatal consequences if untreated. As of writing, confirmatory genetic assays are currently unavailable in the country, and the diagnosis of GS is primarily based on several biochemical laboratory tests. This results in the difficulty with prompt diagnosis of GS in the locality. Case: We present a 52-year-old male who came in with chronic, intermittent paraparesis associated with persistent hypokalemia. A diagnosis of GS was made biochemically based on renal wasting of potassium and magnesium, hypocalciuria, and metabolic alkalosis. Electrolyte correction with lifelong supplementation, and administration of Spironolactone resulted in the resolution of bilateral leg weakness. Electrolyte levels were maintained within normal limits in the outpatient setting. Conclusion GS is an uncommon potentially debilitating disorder that may lead to problematic, potentially fatal consequences to electrolyte abnormalities if left untreated. The lack of awareness and consequent delay in the diagnosis, and the unavailability of confirmatory genetic testing remains a clinical challenge. Timely recognition and initiation of treatment leads to early control of electrolyte levels, and better prognosis.
Gitelman&rsquo ; s Syndrome ; Paraparesis ; Hypokalemia ; Hypomagnesemia ; Spironolactone ; Case Report

Virtually all of the dietary potassium intake is absorbed in the intestine, over 90% of which is excreted by the kidneys regarded as the most important organ of potassium excretion in the body. The renal excretion of potassium results primarily from the secretion of potassium by the principal cells in the aldosterone-sensitive distal nephron (ASDN), which is coupled to the reabsorption of Na⁺ by the epithelial Na⁺ channel (ENaC) located at the apical membrane of principal cells. When Na⁺ is transferred from the lumen into the cell by ENaC, the negativity in the lumen is relatively increased. K⁺ efflux, H⁺ efflux, and Cl^- influx are the 3 pathways that respond to Na⁺ influx, that is, all these 3 pathways are coupled to Na⁺ influx. In general, Na⁺ influx is equal to the sum of K⁺ efflux, H⁺ efflux, and Cl^- influx. Therefore, any alteration in Na⁺ influx, H⁺ efflux, or Cl^- influx can affect K⁺ efflux, thereby affecting the renal K⁺ excretion. Firstly, Na⁺ influx is affected by the expression level of ENaC, which is mainly regulated by the aldosterone-mineralocorticoid receptor (MR) pathway. ENaC gain-of-function mutations (Liddle syndrome, also known as pseudohyperaldosteronism), MR gain-of-function mutations (Geller syndrome), increased aldosterone levels (primary/secondary hyperaldosteronism), and increased cortisol (Cushing syndrome) or deoxycorticosterone (hypercortisolism) which also activate MR, can lead to up-regulation of ENaC expression, and increased Na⁺ reabsorption, K⁺ excretion, as well as H⁺ excretion, clinically manifested as hypertension, hypokalemia and alkalosis. Conversely, ENaC inactivating mutations (pseudohypoaldosteronism type 1b), MR inactivating mutations (pseudohypoaldosteronism type 1a), or decreased aldosterone levels (hypoaldosteronism) can cause decreased reabsorption of Na⁺ and decreased excretion of both K⁺ and H⁺, clinically manifested as hypotension, hyperkalemia, and acidosis. The ENaC inhibitors amiloride and Triamterene can cause manifestations resembling pseudohypoaldosteronism type 1b; MR antagonist spironolactone causes manifestations similar to pseudohypoaldosteronism type 1a. Secondly, Na⁺ influx is regulated by the distal delivery of water and sodium. Therefore, when loss-of-function mutations in Na⁺-K⁺-2Cl^- cotransporter (NKCC) expressed in the thick ascending limb of the loop and in Na⁺-Cl^- cotransporter (NCC) expressed in the distal convoluted tubule (Bartter syndrome and Gitelman syndrome, respectively) occur, the distal delivery of water and sodium increases, followed by an increase in the reabsorption of Na⁺ by ENaC at the collecting duct, as well as increased excretion of K⁺ and H⁺, clinically manifested as hypokalemia and alkalosis. Loop diuretics acting as NKCC inhibitors and thiazide diuretics acting as NCC inhibitors can cause manifestations resembling Bartter syndrome and Gitelman syndrome, respectively. Conversely, when the distal delivery of water and sodium is reduced (e.g., Gordon syndrome, also known as pseudohypoaldosteronism type 2), it is manifested as hypertension, hyperkalemia, and acidosis. Finally, when the distal delivery of non-chloride anions increases (e.g., proximal renal tubular acidosis and congenital chloride-losing diarrhea), the influx of Cl^- in the collecting duct decreases; or when the excretion of hydrogen ions by collecting duct intercalated cells is impaired (e.g., distal renal tubular acidosis), the efflux of H⁺ decreases. Both above conditions can lead to increased K⁺ secretion and hypokalemia. In this review, we focus on the regulatory mechanisms of renal potassium excretion and the corresponding diseases arising from dysregulation.
Humans ; Bartter Syndrome/metabolism* ; Pseudohypoaldosteronism/metabolism* ; Potassium/metabolism* ; Aldosterone/metabolism* ; Hypokalemia/metabolism* ; Gitelman Syndrome/metabolism* ; Hyperkalemia/metabolism* ; Clinical Relevance ; Epithelial Sodium Channels/metabolism* ; Kidney Tubules, Distal/metabolism* ; Sodium/metabolism* ; Hypertension ; Alkalosis/metabolism* ; Water/metabolism* ; Kidney/metabolism*

Pseudohypoparayhyroidism (PHP) is a rare autosomal dominant or recessive genetic disorder characterized by low calcium, high phosphorus, and target organ resistance to parathyroid. The clinical characteristics and genetic features in 4 patients with Type Ib PHP in the Third Xiangya Hospital, Central South University, have been reviewed. All 4 patients had low calcium, high phosphorus, and parathyroid resistance. Among them, 2 patients had slightly elevated thyroid stimulating hormone and mild features of Albright's hereditary osteodystrophy, and one patient had hypokalemia. No guanine nucleotide-binding protein alpha-stimulating activity polypeptide 1 (GNAS) and gene variant associated with hypokalemia were identified using the whole exome sequencing. The results of the methylation-specific multiple ligation-dependent probe amplification showed that there were abnormal methylation of the upstream differentially methylated regions of GNAS in the 4 patients. There were phenotype overlap among the various subtypes of PHP. Detection of GNAS gene methylation in patients with clinical suspicion of Type Ib PHP is helpful for the diagnosis and treatment of PHP.
Humans ; Chromogranins/genetics* ; GTP-Binding Protein alpha Subunits, Gs/genetics* ; Hypokalemia ; Calcium ; Pseudohypoparathyroidism/genetics* ; Phosphorus

OBJECTIVE: To summarize clinical manifestations and results of genetic testing in 12 children with Gitelman syndrome (GS). METHODS: Clinical data of the children was collected. Whole exome sequencing(WES) was carried out to screen potential variants of genomic DNA. Candidate variants were verified by Sanger sequencing. RESULTS: The patients have included 10 boys and 2 girls, whom were diagnosed at between 2.8 to 15.0 year old. Six patients were due to infections, 5 were due to short stature, and 1 was due to lower limb weakness. All patients were found to carry variants of SLC12A3 gene, which included 11 with compound heterozygous variants and 1 with homozygous variant. All of the 19 alleles of the SLC12A3 gene carried by the patients were delineated, which included 15 missense variants, 2 frameshift variants and 2 splice region variants. These variants were unreported previously, which included c.578_582dupCCACC (p.Asn195Profs*109), c.251C>T (p.Pro84Leu) and c.2843G>A (p.Trp948X). CONCLUSION The clinical symptoms of GS in children are atypical and often seen in older children. For children with occasional hypokalemia associated with growth failure, GS should be suspected. The majority of GS children carry two pathogenic variants of the SLC12A3 gene, mainly compound heterozygotes, among which p.Thr60Met is the most common one. The discovery of new variants has enriched the spectrum of SLC12A3 gene variants.
Adolescent ; Child ; Child, Preschool ; DNA ; Female ; Genetic Testing ; Gitelman Syndrome/genetics* ; Humans ; Hypokalemia/genetics* ; Male ; Solute Carrier Family 12, Member 3/genetics*

A boy, aged 1 year and 6 months, was found to have persistent positive urine glucose at the age of 4 months, with polydipsia, polyuria, and growth retardation. Laboratory examinations suggested that the boy had low specific weight urine, anemia, hypokalemia, hyponatremia, hypomagnesemia, metabolic acidosis, glycosuria, acidaminuria, increased fractional excretion of potassium, and decreased tubular reabsorption of phosphate. X-ray examinations of the head, thorax, and right hand showed changes of renal rickets. The slit-lamp examination showed a large number of cystine crystals in the cornea. The genetic testing showed a suspected pathogenic homozygous mutation of the
Amino Acid Transport Systems, Neutral/genetics* ; Cornea ; Cystinosis/genetics* ; Humans ; Hypokalemia ; Infant ; Male ; Mutation ; Rare Diseases