Megalencephalic Leukoencephalopathy

Megalencephalic leukoencephalopathy is a rare inherited leukodystrophy characterized by early-onset macrocephaly, white matter abnormalities, and slow psychomotor decline. Etiology involves mutations in MLC1 or GLIALCAM. Pathophysiology involves defective astrocytic ion and water homeostasis, leading to myelin vacuolation. Diagnosis relies on neuroimaging demonstrating diffuse white matter abnormalities and genetic testing. Management is supportive, focusing on seizure control, physiotherapy, and developmental monitoring; prognosis is generally slowly progressive.