MLC1 encodes a transmembrane protein predominantly expressed in brain astrocytes, particularly at astrocytic endfeet contacting blood vessels and meninges 1. The protein contains eight predicted transmembrane domains and shows low homology with voltage-dependent potassium channel subunits 1. MLC1 plays a crucial role in regulating ion and water homeostasis in the brain by forming protein complexes with GlialCAM, aquaporin-4 (AQP4), and potassium channel KIR4.1 at astrocytic endfeet 2. These complexes are essential for maintaining proper brain volume regulation and blood-brain barrier function 2. Biallelic loss-of-function mutations in MLC1 cause megalencephalic leukoencephalopathy with subcortical cysts (MLC), a rare leukodystrophy characterized by macrocephaly, brain edema, subcortical cysts, and progressive motor dysfunction 13. The disease affects more than 75% of MLC patients, leading to cerebellar ataxia, epilepsy, and cognitive decline 3. Gene therapy studies demonstrate that MLC1 replacement can reverse brain edema and motor deficits even with late-stage intervention, suggesting therapeutic potential for affected patients 3. Additionally, MLC1 variants have been associated with psychiatric disorders including schizophrenia and bipolar disorder 4.