Dent disease is a rare X-linked recessive inherited renal tubular disorder characterized by low molecular weight proteinuria (LMWP), hypercalciuria, nephrocalcinosis, and other clinical features, and can lead to progressive renal failure. It is primarily caused by mutations in the CLCN5 gene. This article reports the case of a 10-year-old male patient of Chinese descent who was incidentally found to have asymptomatic proteinuria during a routine health examination. Comprehensive biochemical testing and clinical evaluation revealed significant LMWP and hypercalciuria, while renal biopsy showed mesangial cell and matrix proliferation. Whole exome sequencing identified a novel deletion mutation in the CLCN5 gene (NM_001127899.4, c.1158delC, p.F387Lfs*42) causing a frameshift and premature termination, which is likely to disrupt its role in chloride/hydrogen ion exchange and endosomal acidification. Bioinformatic analysis indicated the variant is pathogenic. Genetic testing plays an important role in diagnosing rare kidney diseases. Early identification of pathogenic mutations is essential for facilitating timely intervention and appropriate management, potentially enhancing patient outcomes. This report expands the CLCN5 mutation spectrum and contributes to understanding the genetic and molecular mechanisms of Dent disease.
Humans ; Chloride Channels/genetics* ; Dent Disease/genetics* ; Male ; Child ; Computational Biology ; Mutation ; Proteinuria/genetics* ; Hypercalciuria/genetics*

OBJECTIVE: To explore the clinical features and molecular etiology of a patient with Dent disease due to variant of CLCN5 gene. METHODS: A male patient with Dent disease diagnosed at the First Affiliated Hospital of Zhengzhou University in September 2023 was selected as the study subject. Clinical data of the patient were collected. Whole exome sequencing (WES) was carried out for the patient and his family members. Pathogenicity of candidate variant was verified by Sanger sequencing and bioinformatic analysis. This study has been approved by the Medical Ethics Committee of the Hospital (Ethics No. KS-2018-KY-36). RESULTS: The patient, a 15-year-old male, was admitted due to proteinuria and hematuria. Ultrasonography showed diffuse echogenic changes in both kidneys. Renal biopsy revealed structural dysfunction of renal tubules. Electron microscopy revealed minor tubular and glomerular lesions. The patient was found to harbor a hemizygous c.701dupA (p.Y234Ter) variant of the CLCN5 gene, which was derived from his mother. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the variant was rated as pathogenic (PVS1+PM2). Bioinformatic analysis using multiple software predicted the deleterious effect of the variant. CONCLUSION The hemizygous c.701dupA (p.Y234Ter) variant of the CLCN5 gene probably underlay the pathogenesis of Dent disease in this patient. Above finding has enriched the mutational spectrum of the CLCN5 gene.
Adolescent ; Female ; Humans ; Male ; Chloride Channels/genetics* ; Dent Disease/genetics* ; Exome Sequencing ; Mutation ; Pedigree

Distal renal tubular acidosis (dRTA) is characterized by hyperchloremic hypokalemic metabolic acidosis, nephrocalcinosis and metabolic bone disease. It has been associated with Southeast Asian Ovalocytosis (SAO), particularly in malaria endemic region. We present a case of an older adult with dRTA who presented with respiratory failure as a result of hyperchloremic normal anion gap metabolic acidosis, in association with nephrocalcinosis and SAO, however, without hypokalaemia due to concurrent acute kidney injury. Oxygen therapy was able to be weaned off after treatment with alkali supplementation. Distal RTA may be associated with SAO, and early recognition and treatment of dRTA is paramount in preventing complications such as chronic kidney disease, metabolic bone disease and life-threatening respiratory arrest.
Acidosis, Renal Tubular

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*

OBJECTIVES: To study the value of serum fibroblast growth factor 23 (FGF23) in the diagnosis of hypophosphatemic rickets in children. METHODS: A total of 28 children who were diagnosed with hypophosphatemic rickets in Children's Hospital of Nanjing Medical University from January 2016 to June 2021 were included as the rickets group. Forty healthy children, matched for sex and age, who attended the Department of Child Healthcare of the hospital were included as the healthy control group. The serum level of FGF23 was compared between the two groups, and the correlations of the serum FGF23 level with clinical characteristics and laboratory test results were analyzed. The value of serum FGF23 in the diagnosis of hypophosphatemic rickets was assessed. RESULTS: The rickets group had a significantly higher serum level of FGF23 than the healthy control group (P<0.05). In the rickets group, the serum FGF23 level was positively correlated with the serum alkaline phosphatase level (r_s=0.38, P<0.05) and was negatively correlated with maximum renal tubular phosphorus uptake/glomerular filtration rate (r_s=-0.64, P<0.05), while it was not correlated with age, height Z-score, sex, and parathyroid hormone (P>0.05). Serum FGF23 had a sensitivity of 0.821, a specificity of 0.925, an optimal cut-off value of 55.77 pg/mL, and an area under the curve of 0.874 in the diagnosis of hypophosphatemic rickets (P<0.05). CONCLUSIONS Serum FGF23 is of valuable in the diagnosis of hypophosphatemic rickets in children, which providing a theoretical basis for early diagnosis of this disease in clinical practice.
Child ; Humans ; Fibroblast Growth Factor-23 ; Fibroblast Growth Factors ; Familial Hypophosphatemic Rickets/diagnosis* ; Rickets, Hypophosphatemic/diagnosis*

An 18-day-old male infant was admitted to the hospital due to recurrent hyperkalemia for more than 10 days. The neonate had milk refusal and dyspnea. The blood gas analysis revealed recurrent hyperkalemia, hyponatremia and metabolic acidosis. Adrenocortical hormone replacement therapy was ineffective. Additional tests showed a significant increase in aldosterone levels. Family whole exome sequencing revealed that the infant had compound heterozygous in the SCNNIA gene, inherited from both parents. The infant was diagnosed with neonatal systemic pseudohypoaldosteronism type I. The infant's electrolyte levels were stabilized through treatment with sodium polystyrene sulfonate and sodium supplement. The infant was discharged upon clinical recovery. This study provides a focused description of differential diagnosis of salt-losing syndrome in infants and introduces the multidisciplinary management of neonatal systemic pseudohypoaldosteronism type I.
Infant ; Infant, Newborn ; Humans ; Male ; Pseudohypoaldosteronism/genetics* ; Hyperkalemia/etiology* ; Hyponatremia/diagnosis* ; Diagnosis, Differential

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

A series of chemotherapeutic drugs that induce DNA damage, such as cisplatin (DDP), are standard clinical treatments for ovarian cancer, testicular cancer, and other diseases that lack effective targeted drug therapy. Drug resistance is one of the main factors limiting their application. Sensitizers can overcome the drug resistance of tumor cells, thereby enhancing the antitumor activity of chemotherapeutic drugs. In this study, we aimed to identify marketable drugs that could be potential chemotherapy sensitizers and explore the underlying mechanisms. We found that the alcohol withdrawal drug disulfiram (DSF) could significantly enhance the antitumor activity of DDP. JC-1 staining, propidium iodide (PI) staining, and western blotting confirmed that the combination of DSF and DDP could enhance the apoptosis of tumor cells. Subsequent RNA sequencing combined with Gene Set Enrichment Analysis (GSEA) pathway enrichment analysis and cell biology studies such as immunofluorescence suggested an underlying mechanism: DSF makes cells more vulnerable to DNA damage by inhibiting the Fanconi anemia (FA) repair pathway, exerting a sensitizing effect to DNA damaging agents including platinum chemotherapy drugs. Thus, our study illustrated the potential mechanism of action of DSF in enhancing the antitumor effect of DDP. This might provide an effective and safe solution for combating DDP resistance in clinical treatment.
Female ; Male ; Humans ; Cisplatin/pharmacology* ; Disulfiram/pharmacology* ; Testicular Neoplasms/drug therapy* ; Fanconi Anemia/drug therapy* ; Alcoholism/drug therapy* ; Drug Resistance, Neoplasm ; Cell Line, Tumor ; Substance Withdrawal Syndrome/drug therapy* ; Apoptosis ; Antineoplastic Agents/therapeutic use* ; Cell Proliferation

X-linked hypophosphatemia (XLH) represents the most common form of familial hypophosphatemia. Although significant advances have been made in the treatment of bone pathology, patients undergoing therapy continue to experience significantly decreased oral health-related quality of life. The following study addresses this persistent oral disease by further investigating the effect of DMP1 expression on the differentiation of XLH dental pulp cells. Dental pulp cells were isolated from the third molars of XLH and healthy controls and stable transduction of full-length human DMP1 were achieved. RNA sequencing was performed to evaluate the genetic changes following the induction of odontogenic differentiation. RNAseq data shows the upregulation of inhibitors of the canonical Wnt pathway in XLH cells, while constitutive expression of full-length DMP1 in XLH cells reversed this effect during odontogenic differentiation. These results imply that inhibition of the canonical Wnt pathway may contribute to the pathophysiology of XLH and suggest a new therapeutic strategy for the management of oral disease.
Humans ; Familial Hypophosphatemic Rickets ; Wnt Signaling Pathway ; Dental Pulp ; Quality of Life ; Cell Differentiation

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