A novel CLCNKB mutation in a Chinese girl with classic Bartter syndrome: a case report

Abstract

Background Bartter syndrome (BS) is a rare autosomal recessive disorder of salt reabsorption at the thick ascending limb of the Henle loop, characterized by hypokalemia, salt loss, metabolic alkalosis, hyperreninemic hyperaldosteronism with normal blood pressure. BS type III, often known as classic BS (CBS), is caused by loss-of-function mutations in CLCNKB ( chloride voltage-gated channel Kb ) encoding basolateral ClC-Kb. Case presentation We reported a 15-year-old CBS patient with a compound heterozygous mutation of CLCNKB gene. She first presented with vomiting, hypokalemic metabolic alkalosis at the age of 4 months, and was clinically diagnosed as CBS. Indomethacin, spironolactone and oral potassium were started from then. During follow-up, the serum electrolyte levels were generally normal, but the patient showed failure to thrive and growth hormone (GH) deficiency was diagnosed. The recombinant human GH therapy was performed, and the growth velocity was improved. When she was 14, severe proteinuria and chronic kidney disease (CKD) were developed. Renal biopsy showed focal segmental glomerulosclerosis (FSGS) with juxtaglomerular apparatus cell hyperplasia, and genetic testing revealed a point deletion of c.1696delG (p. Glu566fs) and a fragment deletion of exon 2–3 deletions in CLCNKB gene. Apart from the CBS, ostium secundum atrial septal defect (ASD) was diagnosed by echocardiography. Conclusions This is the first report of this compound heterozygous of CLCNKB gene in BS Children. Our findings contribute to a growing list of CLCNKB mutations associated with CBS. Some recessive mutations can induce CBS in combination with other mutations.

A rare presentation of adult Bartter syndrome: a case report

“…The common features in BS are hypokalemia, hypovolemia, hypochloremia, hypercalciuria, hypermagnesuria, secondary hyperaldosteronism, metabolic alkalosis. 7 Main manifestation in this case was fever, myalgia, nausea, cough since one day, decreased appetite and unable to do daily routine. Hypokalemia is a common clinical presentation in BS and the present case showed the renal potassium loss.…”

Bartter syndrome type III with glomerular dysplasia and chronic kidney disease: A case report

“…reported a 15-year-old child with cBS whose creatinine clearance rate was 43 ml/min/1.73 m 2 . His renal puncture suggested focal segmental glomerulosclerosis ( 14 ). Under an electron microscope, focal segmental glomerulosclerosis, glomerular basement membrane thickening, immune complex deposition in the mesangial matrix, vacuolar degeneration of renal tubular epithelial cells, renal interstitial fibrosis and inflammatory cell infiltration were observed ( 14 ).…”

“…His renal puncture suggested focal segmental glomerulosclerosis ( 14 ). Under an electron microscope, focal segmental glomerulosclerosis, glomerular basement membrane thickening, immune complex deposition in the mesangial matrix, vacuolar degeneration of renal tubular epithelial cells, renal interstitial fibrosis and inflammatory cell infiltration were observed ( 14 ). The author puts forward two hypotheses about the changes in renal function in this child: one possibility is that chronic stimulation of RAAS increases the response of ATII to chronic renal dysfunction caused by salt loss nephropathy; the other possibility is that long-term hypokalemia may lead to hypertrophy and renal fibrosis by activating transforming growth factor β (TGF- β ), so the scholar thinks that the renal changes in this child are caused by BS ( 14 ).…”

“…Genotype and clinical features of each cBS and CKD. (TGF-β), so the scholar thinks that the renal changes in this child are caused by BS(14).Le et al reported a 13-year-old Vietnamese boy diagnosed with cBS. His creatinine was 124umol/l, and his GFR was 61 ml/min/ 1.73 m 2…”

A Novel Homozygous CLCNKB Mutation of Classic Bartter Syndrome Presenting with Renal Cysts in 6-year-Old Identical Twin Boys : A Case Report

“…Therefore, we do not clearly confirm whether the mutation was de novo or inherited from their parents. Although Bartter syndrome rarely progresses to endstage renal dis www.chikd.org ease, chronic kidney disease with severe proteinuria deve loped in a substantial number of patients during followup 14,15) . To manage Bartter syndrome in a timely manner, we should carefully take medical history, promptly make a diagnosis, appropriately treat electrolyte imbalance, and finally improve their quality of life.…”