Megalencephalic leukoencephalopathy with subcortical cysts

This code identifies a rare, inherited neurological disorder characterized by an abnormally large brain (megalencephaly) and white matter abnormalities (leukoencephalopathy) with fluid-filled sacs (cysts) located beneath the cerebral cortex. It typically presents in early childhood with macrocephaly, motor delays, and often a slowly progressive course.

Assign this code for patients diagnosed with Megalencephalic Leukoencephalopathy with Subcortical Cysts (MLC). Documentation should clearly indicate the presence of megalencephaly, leukoencephalopathy, and subcortical cysts, often confirmed by neuroimaging studies like MRI. This code is appropriate when the specific genetic diagnosis of MLC is established or strongly suspected based on clinical and imaging findings.

• Ensure documentation specifies "subcortical cysts" to differentiate from other leukoencephalopathies.
• Do not confuse with other forms of leukoencephalopathy without the characteristic subcortical cysts or megalencephaly.
• Consider sequencing this code as the primary diagnosis when it is the reason for the encounter or the main condition being managed.