Dent disease:classification,heterogeneity and diagnosis

Background Dent disease is a rare tubulopathy characterized by manifestations of proximal tubular dysfunction,which occurs almost exclusively in males.It mainly presents symptoms in early childhood and may progress to end-stage renal failure between the 3rd and 5th decades of human life.According to its various genetic basis and to clinical signs and symp-toms,researchers define two forms of Dent disease(Dent diseases 1 and 2)and suggest that these forms are produced by mutations in the CLCN5 and OCRL genes,respectively.Dent diseases 1 and 2 account for 60% and 15% of all Dent disease cases,and their genetic cause is generally understood.However,the genetic cause of the remaining 25% of Dent disease cases remains unidentified.Data sources All relevant peer-reviewed original articles published thus far have been screened out from PubMed and have been referenced.Results Genetic testing has been used greatly to identify mutation types of CLCN5 and OCRL gene,and next-generation sequencing also has been used to identify an increasing number of unknown genotypes.Gene therapy may bring new hope to the treatment of Dent disease.The abuse of hormones and immunosuppressive agents for the treatment of Dent disease should be avoided to prevent unnecessary harm to children.Conclusions The current research progress in classification,genetic heterogeneity,diagnosis,and treatment of Dent disease reviewed in this paper enables doctors and researchers to better understand Dent disease and provides a basis for improved prevention and treatment.

Functional coupling of V-ATPase and CLC-5

Dent’s disease is an X-linked renal tubulopathy characterized by low molecular weight proteinuria, hypercalciuria and progressive renal failure. Disease aetiology is associated with mutations in the CLCN5 gene coding for the electrogenic 2Cl-/H＋ antiporter chloride channel 5 （CLC-5）, which is expressed in the apical endosomes of renal proximal tubules with the vacuolar type H＋-ATPase （V-ATPase）. Initially identified as a member of the CLC family of Cl- channels, CLC-5 was presumed to provide Cl shunt into the endosomal lumen to dissipate H＋ accumulation by V-ATPase, thereby facilitating efficient endosomal acidification. However, recent findings showing that CLC-5 is in fact not a Cl- channel but a 2Cl-/H＋ antiporter challenged this classical shunt model, leading to a renewed and intense debate on its physiological roles. Cl- accumulation via CLC-5 is predicted to play a critical role in endocytosis, as illustrated in mice carrying an artifcial Cl- channel mutation E211A that developed defective endocytosis but normal endo-somal acidification. Conversely, a recent functional analysis of a newly identifed disease-causing Cl- channel mutation E211Q in a patient with typical Dent’s disease confrmed the functional coupling between V-ATPase and CLC-5 in endosomal acidifcation, lending support to the classical shunt model. In this editorial, we will address the current recognition of the physiological role of CLC-5 with a specific focus on the functional coupling of V-ATPase and CLC-5.

Glomerular podocyte dysfunction in inherited renal tubular disease

Background Hereditary renal tubular disease can cause hypercalciuria,acid-base imbalance,hypokalemia,hypomagnesemia,rickets,kidney stones,etc.If these diseases are not diagnosed or treated in time,they can cause kidney damage and electrolyte disturbances,which can be detrimental to the maturation and development of the child.Glomerular involvement in renal tubular disease patients has only been considered recently.Methods We screened 71 papers(including experimental research,clinical research,etc.)about Dent's disease,Gitelman syndrome,and cystinosis from PubMed,and made reference.Results Glomerular disease was initially underestimated among the clinical signs of renal tubular disease or was treated merely as a consequence of the tubular damage.Renal tubular diseases affect glomerular podocytes through certain mechanisms resulting in functional damage,morphological changes,and glomerular lesions.Conclusions This article focuses on the progress of changes in glomerular podocyte function in Dent disease,Gitelman syndrome,and cystinosis for the purposes of facilitating clinically accurate diagnosis and scientific treatment and improving prognosis.