MLC1 and leukoencephalopathy, megalencephalic: Autosomal recessive mutations in Megalencephalic Leukoencephalopathy with subcortical cysts (MLC)1, or dominant heterozygous mutations in GLIALCAM disrupt membrane localization of MLC1 to astrocyte endfeet and astrocyte junctions, where it stabilizes water channels including aquaporin-4 and the inwardly rectifying potassium channel Kir4.1 (Noell et al., 2011; Brignone et al., 2015).