HEPACAM and megalencephalic leukoencephalopathy with subcortical cysts: In the present study, we aimed to reveal the clinical characteristics, including those in long-term follow-up studies, genetic features, and phenotype–genotype relationship in MLC patients with GLIALCAM mutations and generate Glialcam mouse models with autosomal recessive and autosomal dominant inheritance to clarify the disease course and understand the brain pathological features of mouse models with different modes of inheritance.