Bartter Syndrome Unveiled: Unraveling the Masquerade of Neuroregression

Excerpt

To the Editor: A 10-mo-old boy, second born out of non-consanguineous marriage, premorbidly normal with uneventful birth, presented with regression of milestones following onset of seizures over the past 2 mo. Examination revealed subtle dysmorphism with failure to thrive. EEG showed generalised slowing with multifocal discharges. On admission the child was clinically dehydrated with a history of polyuria. MRI brain showed severe diffuse cortical atrophy, subdural collections bilaterally and superficial siderosis in bilateral cerebellar hemispheres (Supplementary Fig. S1). Possibilities of gray matter degenerative brain disorders like neuronal ceroid lipofuscinosis, Menke’s disease and mitochondrial cytopathy were kept. The child had persistent electrolyte imbalance with hyponatremia, hypokalemia, hypocalcemia upto 6.2 mg/dl, hypercalciuria and metabolic alkalosis. Renal ultrasound was normal. A possibility of renal tubulopathy leading to secondary CNS insult was kept and next generation sequencing showed a pathogenic homozygous variant chr1:g.(?_16043792)_(16056509_16056868)del involving the CLCNKB gene, confirming type 3 Bartter syndrome (BS). He was discharged on oral electrolyte supplementation along with indomethacin and enalapril with no further episodes of seizures on levetiracetam and phenytoin. …