Focal cortical dysplasia and Bartter syndrome with refractory epilepsy and neurodevelopmental delay: a rare co-occurrence

Introduction: Focal cortical dysplasia (FCD) is a known cause of early-onset drug-resistant epilepsy (DRE). Bartter syndrome (BS) is a rare renal tubular disorder characterized by hypokalemia, hypomagnesemia, and metabolic alkalosis. Structural brain malformations are not considered part of the Bartter phenotype and the coexistence of these two unrelated disorders has not been previously reported. Case presentation: We present a complex case of a 16-year-old male with a history of DRE, spastic quadriplegia, sensorineural hearing loss, and severe developmental delay. He was born prematurely at 33 weeks following a pregnancy complicated by polyhydramnios and prolonged rupture of membranes. Seizure onset was at 4 months of age and remained poorly controlled despite polytherapy. Electroencephalogram (EEGs) showed focal epileptiform discharges with generalized cortical dysfunction, and magnetic resonance imaging (MRI) revealed right frontal cortical thickening and abnormal signal suggestive of FCD. Persistent hypokalemia with metabolic alkalosis, elevated transtubular potassium gradient (TTKG), antenatal polyhydramnios, and failure to thrive supported a diagnosis of BS. Despite polytherapy, seizure control remained highly sensitive to electrolyte imbalance. Discussion: Metabolic disturbances related to BS may aggravate seizures; they do not explain the presence of a focal cortical malformation. This association most likely represents coincidental coexistence, although an unidentified genetic mechanism cannot be excluded. Conclusions: This case highlights the rare coexistence of FCD and BS. The association may represent coincidental coexistence or an as-yet-unidentified genetic mechanism. Comprehensive genomic evaluation may help clarify potential links between renal tubulopathies and neurodevelopmental epilepsy.