Introduction:
Bartter syndrome is a monogenic salt wasting tubulopathy, characterized by hyponatremia, hypokalemia, hypochloremic metabolic alkalosis, elevated renin-aldosterone levels with normal-to-low blood pressure, hypercalciuria and normal serum magnesium levels. It occurs due to affliction of specific channels in the thick ascending loop of Henle. Classical Bartter syndrome or type 3 Bartter Syndrome is due to CLCNKB mutation. Here, we describe single Centre experience of genetically proven classical BS.
A retrospective observational study was done to analyse the clinical profile and genetic spectrum of classical Bartter syndrome.
Methods:
After retrospective chart review of all children with clinical Bartter syndrome, we enrolled all children with likely pathogenic, pathogenic variant- homozygous or compound heterozygous of CLCNKB gene mutation. Children with incomplete details were excluded. The clinical, biochemical parameters and genetic profile at presentation and follow-up were analyzed.
Results:
9 children with genetic diagnosis of classical BS were enrolled after the screening of 14 patients who satisfied the clinical diagnosis of Bartter syndrome. Male to female ratio- 0.2:1. Median age of presentation was 5 months with infantile presentation in 71%. 57% had antenatally detected polyhydramnios. All babies had failure to thrive and had the triad of polyuria, hypokalemia, hypochloremia with metabolic alkalosis. 57% had AKI at initial presentation. 42% children had seizures. Homozygous pathogenic large deletion of CLCNKB gene involving regions of Exon 1-22 was reported in all children with the clinical phenotype. All were treated with Potassium supplements and prostaglandin inhibitor Indomethacin. 57% needed aldosterone antagonist Spironolactone. Median follow-up period was 1.1 years. 66% had hypercalcemia and hypercalciuria on follow-up. Two children had hypomagnesemia requiring supplements. SNHL and Growth hormone deficiency was detected in one child. Though there was improvement in hydration status, electrolyte balance and weight on follow up, height remained below the 3rd centile in all children.
Conclusions:
Majority of children with Bartter syndrome type 3 (OMIM#607364) from our center presented in infancy with failure to thrive, polyuria, hyponatremia, hypochloraemia, hypokalaemia, and growth retardation. Genetic analysis revealed homozygous deletions involving regions of Exon 1-22 in the CLCNKB gene. 57% had antenatal presentation with polyhydramnios and 71% with hypercalcemia on follow-up.
I have no potential conflict of interest to disclose.
I did not use generative AI and AI-assisted technologies in the writing process.