Early diagnosis of Gitelman syndrome in a young child:A case report

BACKGROUND Gitelman syndrome(GS)is an autosomal recessive renal tubular disorder characterized by renal wasting hypokalemia,metabolic alkalosis,hypomagnesemia,and hypocalciuria.It is usually caused by mutations in the gene SLC12A3,which encodes the thiazide-sensitive Na-Cl cotransporter.GS is not usually diagnosed until late childhood or adulthood.CASE SUMMARY Here,we report the case of a one-year-old girl who was brought to the emergency department due to persistent vomiting for two days.On admission to our hospital,generalized weakness was observed,and laboratory investigations revealed severe hypokalemia(1.9 mmol/L).However,persistent hypokalemia was observed during outpatient follow-up.Suspicion of the GS phenotype was assessed via the patient’s clinical presentation,family history,and biochemical analysis of blood and urine.Further genetic analysis was performed for her and her family by exon-wide sequencing analysis of the gene SLC12A3.The genetic diagnosis of GS was established in the Taiwan region family with three affected individuals,two of whom were children(7 years/17 years)without obvious symptoms,with the youngest being only one year old(patient in our case).CONCLUSION We successfully demonstrated the early diagnosis of GS using family genetic analysis.Any instances of hypokalemia should not be neglected,as early detection of GS with suitable treatment can prevent patients from potentially lifethreatening complications.

Gitelman syndrome caused by a rare homozygous mutation in the SLC12A3 gene:A case report

BACKGROUND Gitelman syndrome(GS)is an unusual,autosomal recessive salt-losing tubulopathy characterized by hypokalemic metabolic alkalosis,hypomagnesemia and hypocalciuria.It is caused by mutations in the solute carrier family 12 member 3(SLC12A3)gene resulting in disordered function of the thiazidesensitive NaCl co-transporter.To date,many types of mutations in the SLC12A3 gene have been discovered that trigger different clinical manifestations.Therefore,gene sequencing should be considered before determining the course of treatment for GS patients.CASE SUMMARY A 55-year-old man was admitted to our department due to hand numbness and fatigue.Laboratory tests after admission showed hypokalemia,metabolic alkalosis and renal failure,all of which suggested a diagnosis of GS.Genome sequencing of DNA extracted from the patient’s peripheral blood showed a rare homozygous mutation in the SLC12A3 gene(NM_000339.2:chr16:56903671,Exon4,c.536T>A,p.Val179Asp).This study reports a rare homozygous mutation in SLC12A3 gene of a Chinese patient with GS.CONCLUSION Genetic studies may improve the diagnostic accuracy of Gitelman syndrome and improve genetic counseling for individuals and their families with these types of genetic disorders.

Gitelman syndrome:A case report

BACKGROUND Gitelman syndrome(GS)is an autosomal recessive salt-losing renal tubulopathy arising from mutations in the thiazide-sensitive Na-Cl cotransporter gene.Due to its low incidence and lack of awareness,GS can be easily misdiagnosed or missed in diagnosis.CASE SUMMARY A 24-year-old male presented with>4 years of repeated limb weakness without any treatment.The previous day,the patient was bitten by ants and showed weakness of the lower limbs.The patient had hypokalemia(1.66-2.83 mmol/L),hypomagnesemia(0.4 mmol/L),hypocalciuria(1.51-2.46 mmol/d),metabolic alkalosis(7.47-7.54),normal blood pressure,and increased activity of aldosterone and plasma renin activity(PRA)(PRA 6.4 and 16.45 ng/mL/h and aldosterone 330.64 and 756.82 pg/mL in the supine and upright position,respectively).In addition,SLCI2A3 gene mutation with GS was diagnosed.Oral and intravenous supplementation with potassium and magnesium was initiated.Serum magnesium returned to 0.48 mmol/L and serum potassium returned to 3.08 mmol/L,alleviating the patient’s fatigue symptoms.CONCLUSION GS should be considered in patients with hypokalemia complicated with hypomagnesemia.Genetic testing is essential to confirm the diagnosis.

Novel compound heterozygous mutation of SLC12A3 in Gitelman syndrome co-existent with hyperthyroidism:A case report and literature review

BACKGROUND Gitelman syndrome(GS)is a rare inherited autosomal recessive tubulopathy,characterized clinically by hypokalemia,hypomagnesemia,hypocalciuria,and metabolic alkalosis,and is caused by an inactivating mutation in SLC12A3.GS is prone to misdiagnosis when occurring simultaneously with hyperthyroidism.It is important to consider the possibility of other diseases when hyperthyroidism is combined with hypokalemia,which is difficult to correct.CASE SUMMARY A female patient with hyperthyroidism complicated with limb weakness was diagnosed with thyrotoxic hypokalemic periodic paralysis for 4 mo.However,the patient’s serum potassium level remained low despite sufficient potassium replacement and remission of hyperthyroidism.GS was confirmed by whole exome and Sanger sequencing.Gene sequencing revealed compound heterozygous mutations of c.488C>T(p.Thr163Met),c.2612G>A(p.Arg871His),and c.1171_1178dupGCCACCAT(p.Ile393fs)in SLC12A3.Protein molecular modeling was performed to predict the effects of the identified missense mutations.All three mutations cause changes in protein structure and may result in abnormal protein function.All previously reported cases of GS coexisting with autoimmune thyroid disease are reviewed.CONCLUSION We have identified a novel compound heterozygous mutation in SLC12A3.The present study provides new genetic evidence for GS.

A case of Gitelman syndrome with homozygous SLC12A3 deletion presenting with epilepsy

Background Gitelman syndrome(GS)is a rare autosomal recessive hereditary renal tubular disorder characterized by hypokalemia,metabolic alkalosis,hypomagnesemia,and hypocalciuria.Case presentation We report a rare case of GS with homozygous loss of SLC12A3 presenting with epilepsy.The patient was a 21-year-old female who sought medical attention for seizures.Her condition primarily manifested as epilepsy,diarrhea,and weakness of limbs.Through genetic analysis,we confirmed the diagnosis of this case and formulated a comprehensive approach for its management.Conclusions This case report extends the clinical symptoms of GS and provides a complete family of GS as a reference for subsequent studies.

Analysis of Mutations of Two Gitelman Syndrome Family SLC12A3 Genes and Proposed Treatments Using Chinese Medicine

Objective： To determine the gene location of two Gitelman syndrome （GS） family SLC12A3 genes and explore treatments using Chinese medicine （CM） prescriptions. Methods： In order to locate the two GS mutations, samples were collected from 11 people from two different pedigrees for direct genetic sequencing and comparison of the 26 exons of SLC12A3. Furthermore, the change of serum potassium was monitored throughout the therapy and those two probands undertook a sequential superposition of Western medicine （including potassium, Panangin and potassium-sparing diuretics） with CM prescription based on Buyang Huanwu Decoction （补阳还五汤） and Sijunzi Decoction （四君子汤）. The treatment included three stages, oral potassium chloride for the first 2 weeks （stage 1）, potassium-sparing diuretic and Panangin with potassium chloride for the next 2 weeks （stage 2）, CM along with the medicine in stage 2 for the final 2 weeks （stage 3）. Results： The three mutations occurring in proband 1 from pedigree 1 were Thr60Met, 965-1_976de113ins12 （small indels mutation） and Ala122Ala （homozygous silent mutation）. Likewise, three mutations, Asn359Lys, Thr382Met and Arg913GIn, appeared in the proband 2 from pedigree Ⅱ. The serum potassium levels increasing from baseline to sequential stages were 1.63 mmol/L （baseline）, 2.5 mmol/L （stage 1）, 3.1 mmol/L （stage 2） and 3.9 mmol/L （stage 3） in the proband 1, and 2.8 mmol/L （baseline）, 3.1 mmol/L （stage 1）, 3.5 mmol/L （stage 2） and 4.3 mmol/L （stage 3） in the proband 2, respectively. The symptoms （numbness of limbs, weakness, palpitations, etc.） of both probands were all alleviated. Conclusions： The mutations of both GS pedigrees can be defined as compound heterozygous mutations, most of which are known as missense mutations. Applying CM could be an appropriate choice for future intervention of GS.

R158Q and G212S,novel pathogenic compound heterozygous variants in SLC12A3 of Gitelman syndrome

The dysfunction of Na^(+)-Cl^(−)cotransporter(NCC)caused by mutations in solute carrier family12,member 3 gene(SLC12A3)primarily causes Gitelman syndrome(GS).In identifying the pathogenicity of R158Q and G212S variants of SLC12A3,we evaluated the pathogenicity by bioinformatic,expression,and localization analysis of two variants from a patient in our cohort.The prediction of mutant protein showed that p.R158Q and p.G212S could alter protein’s three-dimensional structure.Western blot showed a decrease of mutant Ncc.Immunofluorescence of the two mutations revealed a diffuse positive staining below the plasma membrane.Meanwhile,we conducted a compound heterozygous model—Ncc^(R156Q/G210S)mice corresponding to human NCC R158Q/G212S.Ncc^(R156Q/G210S)mice clearly exhibited typical GS features,including hypokalemia,hypomagnesemia,and increased fractional excretion of K^(+)and Mg^(2+)with a normal blood pressure level,which made Ncc^(R156Q/G210S)mice an optimal mouse model for further study of GS.A dramatic decrease and abnormal localization of the mutant Ncc in distal convoluted tubules contributed to the phenotype.The hydrochlorothiazide test showed a loss of function of mutant Ncc in Ncc^(R156Q/G210S)mice.These findings indicated that R158Q and G212S variants of SLC12A3 were pathogenic variants of GS.

New SLC12A3 disease causative mutation of Gitelman's syndrome

Gitelman's syndrome(GS) is a salt-losing tubulopathy with an autosomal recessive inheritance caused by mutations of SLC12A3, which encodes for the thiazidesensitive Na Cl cotransporter. In this study we report a new mutation of SLC12A3 found in two brothers affected by GS. Hypokalemia, hypocalciuria and hyperreninemia were present in both patients while hypomagnesemia was detected only in one. Both patients are compound heterozygotes carrying one well known GS associated mutation(c.2581 C > T) and a new one(c.283 del C) in SLC12A3 gene. The new mutation results in a possible frame-shift with a premature stopcodon(pG ln95 Argfs X19). The parents of the patients, heterozygous carriers of the mutations found in SLC12A3, have no disease associated phenotype. Therefore, the new mutation is causative of GS.

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.