Incomplete distal renal tubular acidosis uncovered during pregnancy:A case report

BACKGROUND Renal tubular acidosis(RTA)is a renal cause of non-anion-gap metabolic acidosis characterized by low urinary ammonia excretion.This condition has a low prevalence,and various congenital and acquired etiologies.To date,only a few cases of idiopathic RTA uncovered during pregnancy have been reported.CASE SUMMARY A previously healthy 32-year-old Korean woman at 30 wk of gestation was admitted to Pusan National University Hospital with preterm labor.At admission,the patient presented with hypokalemia,non-anion-gap metabolic acidosis,and nephrocalcinosis.Distal RTA was diagnosed based on laboratory blood and urine findings and imaging examinations.Various tests,including next-generation gene sequencing panels for nephropathy,were performed to determine the etiology of the disease,which indicated that it was idiopathic.The patient received sodium bicarbonate and potassium chloride supplementation.After 3 wk,she delivered a baby who was subsequently diagnosed with corpus callosum agenesis and colpocephaly.During regular follow-ups for 6 mo postpartum,her hypokalemia and metabolic acidosis were gradually resolved,and medications eventually discontinued.CONCLUSION Herein we describe a case of idiopathic distal RTA discovered during pregnancy.Hypokalemia and metabolic acidosis resolved spontaneously after delivery.

Renal calcification in children with renal tubular acidosis:What a paediatrician should know

Renal tubular acidosis(RTA)can lead to renal calcification in children,which can cause various complications and impair renal function.This review provides pediatricians with a comprehensive understanding of the relationship between RTA and renal calcification,highlighting essential aspects for clinical manage-ment.The article analyzed relevant studies to explore the prevalence,risk factors,underlying mechanisms,and clinical implications of renal calcification in children with RTA.Results show that distal RTA(type 1)is particularly associated with nephrocalcinosis,which presents a higher risk of renal calcification.However,there are limitations to the existing literature,including a small number of studies,heterogeneity in methodologies,and potential publication bias.Longitudinal data and control groups are also lacking,which limits our understanding of longterm outcomes and optimal management strategies for children with RTA and renal calcification.Pediatricians play a crucial role in the early diagnosis and management of RTA to mitigate the risk of renal calcification and associated complications.In addition,alkaline therapy remains a cornerstone in the treatment of RTA,aimed at correcting the acid-base imbalance and reducing the formation of kidney stones.Therefore,early diagnosis and appropriate therapeutic interventions are paramount in preventing and managing renal calcification to preserve renal function and improve long-term outcomes for affected children.Further research with larger sample sizes and rigorous methodologies is needed to optimize the clinical approach to renal calcification in the context of RTA in the pediatric population.

Distal renal tubular acidosis:genetic causes and management

Background Distal renal tubular acidosis(dRTA)is a kidney tubulopathy that causes a state of normal anion gap metabolic acidosis due to impairment of urine acidification.This review aims to summarize the etiology,pathophysiology,clinical findings,diagnosis and therapeutic approach of dRTA,with emphasis on genetic causes of dRTA.Data sources Literature reviews and original research articles from databases,including PubMed and Google Scholar.Manual searching was performed to identify additional studies about dRTA.Results dRTA is characterized as the dysfunction of the distal urinary acidification,leading to metabolic acidosis.In pediatric patients,the most frequent etiology of dRTA is the genetic alteration of genes responsible for the codification of distal tubule channels,whereas,in adult patients,dRTA is more commonly secondary to autoimmune diseases,use of medications and uropathies.Patients with dRTA exhibit failure to thrive and important laboratory alterations,which are used to define the diagnosis.The oral alkali and potassium supplementation can correct the biochemical defects,improve clinical manifestations and avoid nephrolithiasis and nephrocalcinosis.Conclusions dRTA is a multifactorial disease leading to several clinical manifestations.Clinical and laboratory alterations can be corrected by alkali replacement therapy.

Hyporeninemic hypoaldosteronism and diabetes mellitus:Pathophysiology assumptions,clinical aspects and implications for management

Patients with diabetes mellitus(DM) frequently develop electrolyte disorders,including hyperkalemia.The most important causal factor of chronic hyperkalemia in patients with diabetes is the syndrome of hyporeninemic hypoaldosteronism(HH),but other conditions may also contribute.Moreover,as hyperkalemia is related to the blockage of the renin-angiotensin-aldosterone system(RAAS) and HH is most common among patients with mild to moderate renal insufficiency due to diabetic nephropathy(DN),the proper evaluation and management of these patients is quite complex.Despite its obvious relationship with diabetic nephropathy,HH is also related to other microvascular complications,such as DN,particularly the autonomic type.To confirm the diagnosis,plasma aldosterone concentration and the levels of renin and cortisol are measured when the RAAS is activated.In addition,synthetic mineralocorticoid and/or diuretics are used for the treatment of this syndrome.However,few studies on the implications of HH in the treatment of patients with DM have been conducted in recent years,and therefore little,if any,progress has been made.This comprehensive review highlights the findings regarding the epidemiology,diagnosis,and management recommendations for HH in patients with DM to clarify the diagnosis of this clinical condition,which is often neglected,and to assist in the improvement of patient care.

Fanconi-Bickel syndrome as an example of marked allelic heterogeneity

Renal tubular acidosis （RTA） encompasses many re-nal tubular disorders characterized by hyperchloremic metabolic acidosis with a normal anion gap. Untreated patients usually complain of growth failure, osteoporo-sis, rickets, nephrolithiasis and eventually renal insuff-ciency. Fanconi-Bickel syndrome （FBS） is an example of proximal RTA due to a single gene disorder; it is caused by defects in the facilitative glucose transporter 2 gene that codes for the glucose transporter protein 2 ex-pressed in hepatocytes, pancreatic β-cells, enterocytes and renal tubular cells. It is a rare inherited disorder of carbohydrate metabolism manifested by huge hepa-tomegaly [hence it is classified as glycogen storage disease （GSD） type XI; GSD XI], severe hypophospha-temic rickets and failure to thrive due to proximal renal tubular dysfunction leading to glucosuria, phosphaturia, generalized aminoaciduria, bicarbonate wasting and hy-pophosphatemia. The disorder has been reported from all parts of Europe, Turkey, Israel, Arabian countries, Ja-pan and North America. Many mutant alleles have been described, its exact frequency is unknown and there is no single mutation found more frequently than the oth-ers. The presence of consanguinity in affected families suggests an autosomal recessive pattern of inheritance. New cases of FBS have been recently reported in the Middle and Far East in collaboration with specialized centers. Two novel mutations have been discovered in two unrelated Egyptian families. The first was two bases deletion, guanine and adenine, （c.253_254delGA） causing a frameshift mutation （p. Glu85fs） and the sec-ond is mutation in exon6 in splicing acceptor site with intron5 （c.776-1G〉C or IVS5-1G〉A）. Moreover, a new different mutation was described in a 3 year old Indian boy.