Long-Term Indomethacin Treatment in a Chinese Child with Gitelman Syndrome: Case Report and Literature Review on its Efficacy and Tolerance

BACKGROUND Gitelman syndrome (GS) is a rare inherited autosomal recessive salt-losing renal tubulopathy. Early-onset GS is difficult to differentiate from Bartter syndrome (BS). It has been reported in some cases that cyclooxygenase (COX) inhibitors, which pharmacologically reduce prostaglandin E2(PGE2) synthesis, are helpful for GS patients, especially in children, but the long-term therapeutic effect has not yet been revealed. CASE REPORT A 4-year-old boy was first brought to our hospital for the chief concern of short stature and growth retardation. Biochemical tests demonstrated severe hypokalemia, hyponatremia, and hypochloremic metabolic alkalosis. The patient's serum magnesium was normal. He was diagnosed with BS and treated with potassium supplementation and indomethacin and achieved stable serum potassium levels and slow catch-up growth. At 11.8 years of age, the patient showed hypomagnesemia and a genetic test confirmed that he had GS with compound heterozygous mutations in the SLC12A3 gene. At the age of 14.8 years, when indomethacin had been taken for nearly 10 years, the boy reported having chronic stomachache, while his renal function remained normal. After proton pump inhibitor and acid inhibitor therapy, the patient's symptoms were ameliorated, and he continued to take a low dose of indomethacin (37.5 mg/d divided tid) with good tolerance. CONCLUSIONS Early-onset GS in childhood can be initially misdiagnosed as BS, and gene detection can confirm the final diagnosis. COX inhibitors, such as indomethacin, might be tolerated by pediatric patients, and long-term therapy can improve the hypokalemia and growth retardation without significant adverse effects.

Novel heterozygous mutations of SLC12A3 gene in a Chinese pedigree with Gitelman syndrome: A care-compliant case report

RATIONALE

The diagnosis of Gentleman syndrome (GS) is usually delayed because the clinical symptoms are easily mistaken.

PATIENT CONCERNS

A 19-year-old male patient was referred to endocrinology due to intermittent twitch of extremities for approximately 7 years.

DIAGNOSES

The diagnosis of GS was made based on the laboratory and gene detection results. We identified 2 new variants in the SLC12A3 gene [c.857 A > C (exon7) and c.2089_2095del (exon17)] in his Asian family.

INTERVENTIONS

The patient received the treatment of potassium chloride sustained release tablets, potassium magnesium aspartate and spironolactone. After given potassium supplement through enema, his serum potassium level was corrected to normal.

OUTCOMES

The electrolyte imbalance including hypokalemia and hypomagnesemia were improved with a remission of the clinical manifestations. But the patient's condition still could not remain stable for his irregular oral potassium supplementation during the follow-up of nearly 3 months.

LESSONS

Our finding broadens the variant spectrum of SLC12A3 and contributes to a more quickly genetic counseling. As a result, when a patient presents with persistent, unspecified, and inadequately treated hypokalemia, tests for GS should indeed be considered. For suspected cases of GS, genetic testing should always be considered in the diagnosis.

The challenges of diagnosis and management of Gitelman syndrome

Gitelman syndrome is an inherited tubulopathy characterized by renal salt wasting from the distal convoluted tubule. Defects in the sodium chloride cotransporter (encoded by SLC12A3) underlie this autosomal recessive condition. This article focuses on the specific challenges of diagnosing and treating Gitelman syndrome, with use of an illustrative case report. Symptoms relate to decreased serum potassium and magnesium levels, which include muscle weakness, tetany, fatigue and palpitations. Sudden cardiac deaths have been reported. Making a diagnosis may be difficult given its rarity but is important. A knowledge of the serum and urine biochemical picture is vital to distinguish it from a broad differential diagnosis, and application of genetic testing can resolve difficult cases. There is a group of Gitelman syndrome heterozygous carriers that experience symptoms and electrolyte disturbance and these patients should be managed in a similar way, though here genetic investigations become key in securing a difficult diagnosis. Potassium and magnesium replacement is the cornerstone of treatment, though practically this can be hard for patients to manage and often does not fully relieve symptoms even when serum levels are normalized. Challenges arise due to the lack of randomized controlled trials focussing on treatment of this rare disease; hence, clinicians endorse strategies in line with correction of the underlying pathophysiology such as sodium loading or pharmacological treatments, which seem to help some patients. Focussed dietary advice and knowing the best tolerated preparations of potassium and magnesium medications are useful tools for the physician, as well as an awareness of the specific burdens that this patient group face in order to signpost appropriate support.

Systemic lupus erythematosus complicated by a Gitelman-like syndrome in an 8-year-old girl

An 8-year-old girl with recently diagnosed Systemic Lupus Erythematosus (SLE) (class 4 lupus nephritis with autoimmune hemolytic anemia) presented to the pediatric nephrology clinic with polyuria, tiredness and cramps; laboratory investigations revealed refractory hypokalemia, hypomagnesemia, metabolic alkalosis, hypocalciuria and hyperchloriuria. There was no history of diuretic administration. These features were consistent with the Gitelman syndrome. She required large doses of potassium and magnesium supplementation along with spironolactone, for normalization of the serum potassium and magnesium levels. Immunosuppressive therapy was continued with cyclophosphamide pulses administered on a monthly basis. The doses of potassium and magnesium supplements were tapered off over the next 6 months. The clinical exome sequencing was negative for any mutations in the SLC12A3 gene. An 'acquired' form of Gitelman syndrome has been reported earlier in association with Sjogren syndrome and systemic sclerosis. Though tubular disorders such as renal tubular acidosis have been reported in association with SLE, a Gitelman-like syndrome has not been reported earlier. This case adds Gitelman-like tubulopathy to the clinical spectrum of tubular disorders complicating SLE.

Gitelman's syndrome with hyperphosphatemia, effectively responding to single oral magnesium oxide administration: A case report

RATIONALE

The Gitelman's syndrome (GS) is characterized by metabolic alkalosis, hypokalemia, hypomagnesemia, and hypocalciuria. However, the involvement of this deranged electrolyte balance in patients with GS in parathyroid hormone action has not been known.

PATIENT CONCERNS

We report a 34-year-old woman with muscle weakness and tetany/seizures caused by electrolyte imbalance. She had hyperphosphatemia and hypocalciuric hypocalcemia in addition to severe hypomagnesemia with low potassium in the absence of metabolic alkalosis. We identified 2 heterozygous mutations in the solute carrier family 12 member 3 gene in this case (c.1732G>A, p.Val578Met and c.2537_38delTT, p.846fs) by targeted sequence for all causative genes of salt-losing tubulopathies.

DIAGNOSES

A diagnosis of GS. Hypocalcemia and hyperphosphatemia were suggested to relate with the secondary obstruction of appropriate parathyroid hormone release following severe hypomagnesemia in GS.

INTERVENTIONS

She was treated with single oral magnesium oxide administration.

OUTCOMES

The electrolyte imbalance including hypocalcemia and hyperphosphatemia were resolved with a remission of clinical manifestations.

LESSONS

These observations, in this case, suggest that even severe hypomagnesemia caused by GS was associated with resistance to appropriate parathyroid hormone secretion. Through this case, we recognize that secondary hypoparathyroidism would be triggered by severe hypomagnesemia in GS.

Proinflammatory/profibrotic effects of aldosterone in Gitelman's syndrome, a human model opposite to hypertension

PURPOSE

Aldosterone proinflammatory/profibrotic effects are mediated by the induction of mononuclear leucocytes (MNL) to express oxidative stress (OxSt)-related proteins, such as p22^phox, and by the activation of RhoA/Rho kinase pathway. Gitelman's syndrome (GS), an autosomal recessive tubulopathy, is an interesting opposite model to hypertension, being characterized by hypokalemia, activation of renin-angiotensin-aldosterone system yet normo/hypotension and lack of cardiovascular-renal remodeling. We aimed to evaluate the proinflammatory/profibrotic effect of aldosterone in MNL of 6 GS patients compared with 6 healthy subjects (HS).

METHODS

p22^phox expression and MYPT-1 phosphorylation status, a marker of RhoA/Rho kinase pathway activation, were evaluated in MNL of GS patients and HS at baseline and after incubation with aldosterone (1 × 10^-8 M) alone or with canrenone (1 × 10^-6 M).

RESULTS

At basal condition, p22^phox expression was significantly higher in HS than in GS patients (1.02 ± 0.05 densitometric unit (du) vs 0.40 ± 0.1 du, respectively). Aldosterone significantly increased p22^phox expression in HS and this effect was reversed by coincubation with canrenone (1.4 ± 0.05 du and 1.09 ± 0.03 du, respectively). No significant change was reported in GS after incubation of MNL with aldosterone and/or canrenone compared with basaline. Even MYPT-1 phosphorylation was significantly higher in HS compared with GS patients at basal condition (1.16 ± 0.1 du vs 0.69 ± 0.07, respectively). Aldosterone significantly increased MYPT-1 phosphorylation only in HS (1.37 ± 0.1 du vs 0.83 ± 0.12 du in GS).

CONCLUSIONS

GS patients seem to be protected by the OxSt status induced by aldosterone and revealed in HS. This human model could provide additional clues to highlight the proinflammatory/cardiovascular remodeling effects of aldosterone.

Increased urinary prostaglandin E2 metabolite: A potential therapeutic target of Gitelman syndrome

BACKGROUND

Gitelman syndrome (GS), an inherited autosomal recessive salt-losing renal tubulopathy caused by mutations in SLC12A3 gene, has been associated with normal prostaglandin E2 (PGE2) levels since 1995 by a study involving 11 clinically diagnosed patients. However, it is difficult to explain why cyclooxygenase-2 (COX2) inhibitors, which pharmacologically reduce PGE2 synthesis, are helpful to patients with GS, and few studies performed in the last 20 years have measured PGE2 levels. The relationships between the clinical manifestations and PGE2 levels were never thoroughly analyzed.

METHODS

This study involved 39 GS patients diagnosed by SLC12A3 gene sequencing. Plasma and 24-h urine samples as well as the clinical data were collected at admission. PGE2 and PGEM levels were detected in plasma and urine samples by enzyme immunoassays. The in vivo function of the sodium-chloride co-transporter (NCC) in GS patients was evaluated using a modified thiazide test. The association among PGE2 levels, clinical manifestations and the function of NCC in GS patients were analyzed.

RESULTS

Significantly higher levels of urinary and plasma PGEM were observed in GS patients than in the healthy volunteers. Higher urinary PGEM levels indicated more severe clinical manifestations and NCC dysfunction estimated by the increase of Cl- clearance. A higher PGEM level was found in male GS patients, who showed earlier onset age and more severe hypokalemia, hypochloremia and metabolic alkalosis than female GS patients. No relationship between renin angiotensin aldosterone system activation and PGEM level was observed.

CONCLUSIONS

Higher urinary PGEM levels indicated more severe clinical manifestations and NCC dysfunction in GS patients. COX2 inhibition might be a potential therapeutic target in GS patients with elevated PGEM levels.

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 () and Sijunzi Decoction (). 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 I were Thr60Met, 965-1_976del13ins12 (small indels mutation) and Ala122Ala (homozygous silent mutation). Likewise, three mutations, Asn359Lys, Thr382Met and Arg913Gln, 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.

Gitelman syndrome as a cause of psychomotor retardation in a toddler

INTRODUCTION

Gitelman syndrome (GS) is a very rare autosomal recessive tubulopathy due to loss-of-function or mutation in solute carrier family12, member 3 gene (SLC12A3 gene) encoding thiazide-sensitive NaCl co-transporter in the distal convoluted tubule, leading to hypokalemia, metabolic alkalosis, hypomagnesemia, hypocalciuria and low-to-normal blood pressure. Clinical signs are mostly secondary to chronic hypokalemia and include dizziness, fatigue, constipation and weakness. Patients can also present with muscle cramps, tetany, fatigue and convulsions due to severe metabolic alkalosis or hypomagnesemia. Manifestations of GS are rarely apparent before the age of five, and the syndrome is usually diagnosed during adolescence or adulthood. Here we describe a case of GS presenting in infancy with hypokalemia and psychomotor retardation.

CASE REPORT

We present an 18-month-old boy who presented with psychomotor retardation and failure to thrive. Investigations revealed hypokalemia at 2.7 mmol/L, metabolic alkalosis, hypocalciuria and normal serum magnesium level. The diagnoses of Barter syndrome (BS) and Gitelman syndrome (GS) were considered. Genetic studies confirmed the diagnosis of GS and three different mutations of in SLC12A3 gene were detected. Two mutations (c.2576T>C and c.2929C>Ty) were considered as causal ones, with the patient´s parents being the heterozygous carriers. Oral potassium supplementation resulted in normalisation of the hypokalemia and psychomotor improvement.

CONCLUSION

We report a rare case of psychomotor retardation occurring at an early age in genetically confirmed GS. In spite of being a rare disorder, GS has to be considered in children with developmental delay and muscle weakness. With adequate treatment, GS patients have an excellent prognosis.

[Clinical analysis of 17 cases of Gitelman syndrome]

OBJECTIVE

To analyze the clinical and laboratory characteristics of Gitelman syndrome.

METHODS

Seventeen patients with Gitelman syndrome (male/female: 11/6) were analyzed for their clinical symptoms, laboratory test results, imaging findings, treatments and outcomes.

RESULTS

Fifteen of the 17 patients presented with varying degrees of lower limb weakness, and 8 experienced flaccid paralysis. The laboratory tests showed hypokalemia (17/17), hypomagnesemia (17/17) and hypocalcemia (17/17). Blood renin activity (17/17), angiotensin II (14/17) and aldosterone levels (7/17) were significantly higher in the patients than in normal subjects. The symptoms were relieved by potassium alone or in combination with indomethacin, spironolactone and other potassium magnesium asparaginate, but the serum potassium and magnesium failed to recover the normal levels after the treatments.

CONCLUSION

The primary clinical manifestations of Gitelman syndrome are lower extremity weakness with hypokalemia and hypomagnesemia. Combined drug therapies including potassium, magnesium, aldosterone antagonists and other drugs are recommended. The prognosis of the patients is favorable.

Gitelman's syndrome: a pathophysiological and clinical update

Gitelman's syndrome (GS), also known as familial hypokalemic hypomagnesemia, is a rare autosomal recessive hereditary salt-losing tubulopathy, characterized by hypokalemic metabolic alkalosis, hypomagnesemia, and hypocalciuria, which is usually caused by mutations in the SLC12A3 gene encoding the thiazide-sensitive sodium chloride contrasporter. Because 18-40% of suspected GS patients carry only one SLC12A3 mutant allele, large genomic rearrangements must account for unidentified mutations. The clinical manifestations of GS are highly variable in terms of age at presentation, severity of symptoms, and biochemical abnormalities. Molecular analysis in our sibling's patients revealed compound heterozygous mutations in the coding region of SLC12A3 as underlying their disease. Such compound heterozygosity can result in disease phenotype for such loss of function mutations in the absence of homozygosis through consanguineous inheritance of mutant alleles, identical by descent. Missense mutations account for approximately 70% of the mutations in GS, and there is a predisposition to large rearrangements caused by the presence of repeated sequences within the SLC12A3. We report two adult male siblings of Jewish origin with late onset GS, who presented in their fifth decade of life with muscle weakness, hypokalemia, hypomagnesaemia, and metabolic alkalosis. Rapid clinical and biochemical improvement was achieved by replacement therapy with potassium and magnesium.

Eplerenone improved hypokalemia in a patient with Gitelman's syndrome

A 47-year-old woman presented with hypokalemia (2.4 mmol/L). She also had hypomagnesemia, hypocalciuria, and hyperreninemic hyperaldosteronism. Sequence analysis revealed a compound heterozygous mutation, R655C and R955Q, in the SLC12A3 gene. These findings were compatible with Gitelman's syndrome (GS). Eplerenone, a selective aldosterone blocker, in combination with oral potassium chloride improved serum potassium level (3.6 mmol/L) with no apparent adverse effect. Although eplerenone has an advantage over spironolactone for its selective affinity for the aldosterone receptor, the efficacy and safety of eplerenone for GS is little understood. Our observation suggests that eplerenone is a useful treatment option for GS.

Diagnosis and clinical approach in Gitelman's syndrome

Hypokalemia, defined as a plasma potassium concentration <3.5 mmol/l, is the most common electrolyte abnormality encountered in our clinical practice. Unfortunately, in many cases, the etiologies were unclear and resulted in a wrong treatment. Indeed, the true etiology could be such a 'rare' one and could be found by doing a comprehensive work up. One of this is Gitelman's syndrome, a rare genetic disorder characterized by hypokalemic alkalosis, hypomagnesemia, hypocalciuria, and secondary aldosteronism without hypertension. Since this disorder is found in 1% Caucasian populations, this is one of the most frequently inherited renal tubular disorders. A 27 year old man came to emergency room with weakness and generalised muscle cramps. He was investigated three months before for a similar electrolyte disturbance which was found to be inconclusive. The routine laboratory data in emergency room revealed a potassium concentration of 2.3 mmol/l. He had never used diuretics or hormonal therapy nor had history of vomiting or diarrhea. He had normal blood pressure and the blood gas analysis revealed metabolic alkalosis. On his ECG (electrocardiography), we found the prominent U wave. Despite his low concentration of serum potassium and cloride, the concentration of these electrolytes in urine were extremely high. We also found hipomagnesemia. The calcium concentration in serum was normal with slightly hypocalciuria. Even with aggressive oral and intravenous potassium suplementation, the patient remained hypokalemic. In cases when the etiology of hypokalemia is unclear, we should perform some investigations to confirm the diagnosis and give the proper treatment. In Gitelman's syndrome, where the defect in the distal tubule cannot be corrected, the treatment must be a life-long. Most patients require oral potassium and magnesium supplementation, since drug therapy is usually incompletely effective.

The pharmacological characteristics of molecular-based inherited salt-losing tubulopathies

CONTEXT

Our understanding of inherited salt-losing tubulopathies has improved with recent advances in molecular genetics. However, the terminology of Bartter syndrome and Gitelman syndrome does not always accurately reflect their pathophysiological basis or clinical presentation, and some patients are difficult to diagnose from their clinical presentations.

OBJECTIVE

In the present study, we conducted molecular analysis and diuretic tests for patients with inherited salt-losing tubulopathies to clarify the pharmacological characteristics of these disorders.

PATIENTS

We detected mutations and subsequently conducted diuretic tests using furosemide and thiazide for 16 patients with salt-losing tubulopathies (two with SLC12A1; two with KCNJ1; nine with CLCNKB; and three with SLC12A3).

RESULTS

Patients with SLC12A1 mutations showed no response to furosemide, whereas those with SLC12A3 mutations showed no response to thiazide. However, patients with CLCNKB mutations showed no response to thiazide and a normal response to furosemide, and those with KCNJ1 mutations showed a good response to both diuretics. This study revealed the following characteristics of these disorders: 1) subjects with CLCNKB mutations showed one or more biochemical features of Gitelman syndrome (including hypomagnesemia, hypocalciuria, and fractional chloride excretion insensitivity to thiazide administration); and 2) subjects with KCNJ1 mutations appeared to show normal fractional chloride excretion sensitivity to furosemide and thiazide administration.

CONCLUSIONS

These results indicate that these disorders are difficult to distinguish in some patients, even when using diuretic challenge. This clinical report provides important findings that can improve our understanding of inherited salt-losing tubulopathies and renal tubular physiology.

Gitelman syndrome with mental retardation: a case report

Gitelman syndrome (GS), an inherited disorder due to loss of function in mutations of the gene encoding the distal convoluted tubule Na-Cl cotransporter (NCCT), is characterized by hypokalemia metabolic alkalosis, hypomagnesemia and hypocalciuria. A 18-year-old girl was admitted to our hospital with a history of muscle weakness and transient tetanic episodes affecting bilateral hands. Transient tetanic episodes had been noted over 2 years. The laboratory tests revealed hypokalemia, hypomagnesemia, metabolic alkalosis and hypocalciuria. We started intravenous magnesium and potassium infusion. Tetanic episodes disappeared, but plasma levels of magnesium and potassium did not recover to normal range. On the fifth day, indomethacin and triamterene were administrated. On the seventh day, plasma levels of magnesium and potassium were normalized. The patient was discharged from the hospital.

A case of nephrotic syndrome with Gitelman's syndrome

Nephrotic syndrome, though common in children, association of it with Gitelman's syndrome (GS) is a rare occurrence. Very few cases have been reported in the medical literature so far. Here we report a case of nephrotic syndrome with frequent relapses and remissions on intermittent steroid and diuretic therapy. Patient was restarted on steroids and frusemide. Puffiness of face, bipedal edema and oliguria improved but patient developed tingling numbness in both limbs, perioral numbness and carpopedal spasm. On investigation she was found to have proteinuria, metabolic alkalosis, hypokalemia, hypocalcemia, hypomagnesemia and hyperreninemia with normal blood pressure.

[Generalized seizures as onset of Gitelman's syndrome]

Gitelman's syndrome is a rare autosomal recessive syndrome presenting with hypocalciuria, hypomagnesiemia and hypokalemic metabolic alkalosis. This case reports a patient admitted with generalized seizures with the above-mentioned biochemical abnormalities, thus representing a rare onset of Gitelman's syndrome which - to our knowledge - has not been described previously. The patient had a homozygote deletion of the CLC-KB gene, CLCNKB. The case was successfully treated by correcting hypokalemia and hypomagnesiemia with supplemental potassium and magnesium.

Hypocalciuria in patients with Gitelman syndrome: role of blood volume

BACKGROUND

Hypocalciuria is common in patients with Gitelman syndrome (GS), and its cause primarily is enhanced renal reabsorption of calcium in the proximal tubule in response to hypovolemia, judged by recent studies in animals.

STUDY DESIGN

Uncontrolled trial in cases and controls to evaluate the effect of acute reexpansion of extracellular fluid volume (ECFV) on urine calcium excretion in patients with GS.

SETTING & PARTICIPANTS

8 patients with GS and 8 sex- and age-matched healthy control subjects (CSs) were enrolled in an academic medical center.

PREDICTOR

ECFV expansion with isotonic saline at 1 L/h for 3 hours.

OUTCOMES & MEASUREMENTS

Urinary calcium excretion was measured hourly for 6 hours, and subsequent 18-hour urine was analyzed as a single collection; hormones and electrolytes were measured.

RESULTS

Patients with GS had hypokalemia, metabolic alkalosis, hypomagnesemia, severe hypocalciuria (urine calcium-creatinine ratio, 0.006 +/- 0.002 versus 0.08 +/- 0.02 mg/mg [0.02 +/- 0.01 versus 0.22 +/- 0.05 mmol/mmol]; P < 0.005), and a mild degree of ECFV contraction. Sodium excretion and creatinine clearance rates were similar to those in CSs. In patients with GS, saline infusion increased ECFV, which caused a significantly greater sodium excretion rate, but there was only a small increase in calcium excretion rate, in both the first 6 hours (0.04 +/- 0.02 mg/min [1.0 +/- 0.6 micromol/min]) and subsequent 18-hour period (0.02 +/- 0.01 mg/min [0.4 +/- 0.2 micromol/min]), as in CSs. Notwithstanding, their calcium excretion rate was still much less than that in CSs before volume repletion (0.13 +/- 0.04 mg/min [3.2 +/- 1.0 micromol/min]).

LIMITATION

Patients with GS did not become euvolemic on a long-term sodium chloride supplementation because they excreted sodium chloride so rapidly.

CONCLUSION

Hypovolemia is not the sole cause of hypocalciuria in patients with GS.

Syndrome de Gitelman et grossesse: à propos d'un cas et revue de la littérature

Gitelman syndrome (GS) is a tubulopathy characterized by hypokaliemia, hypomagnesiemia, metabolic alkalosis and hypocalciuria. We report a case of a 33-year-old pregnant woman with Gitelman Syndrome. Oral potassium chloride and magnesium citrate were prescribed and the course of the pregnancy was uneventful with vaginal delivery at term. The impact of GS on the physiologic adaptations to pregnancy is not well-known, with few reports to date. Monitoring of serum potassium and magnesium levels with supplementation, amniotic fluid and fetal growth is required to prevent obstetrical and fetal complications in a patient with GS.

C1q nephropathy in association with Gitelman syndrome: a case report

There have been rare reports of glomerulopathies developing in patients with Bartter syndrome (BS) and its milder variant, Gitelman syndrome (GS). We present the first case of C1q nephropathy (C1qN) in an African American child with GS. This child was diagnosed with GS at 9 years of age and subsequently developed nephrotic range proteinuria 3 years later. Renal biopsy revealed mesangial hypercellularity and focal segmental glomerulosclerosis (FSGS). The segmental lesions were generally located at the vascular pole. Dominant C1q (2+) staining along with IgG (1-2+) was demonstrated in the mesangium, which correlated with scattered electron dense mesangial deposits demonstrated by electron microscopy. Treatment with an angiotensin-converting enzyme inhibitor led to an improvement in proteinuria to near-normal values (urine protein/creatinine ratio down to 0.5), but the creatinine clearance declined to approximately 58 ml/min/1.73 m(2). This case highlights the possible association between the milder hypokalemic tubulopathy, GS, and glomerular disease, including C1qN. Prompt evaluation of proteinuria with renal biopsy in these patients is recommended to detect significant glomerular pathology. Further research is needed to define risk factors for this complication.