Megalencephalic Leukoencephalopathy with Subcortical Cysts: Causes, Symptoms, and Treatment
Medically reviewed by Harsha Moole, MD, Internal Medicine. Last reviewed: October 2, 2026.
What kind of doctor treats Megalencephalic Leukoencephalopathy with Subcortical Cysts?
A neurologist, a doctor specializing in the brain and nervous system, usually leads care, often a pediatric neurologist for children. A primary care doctor helps coordinate visits and connects families with therapists and specialists. A direct primary care or concierge doctor can be a first stop for an evaluation and can refer you to a specialist when needed.
What is megalencephalic leukoencephalopathy with subcortical cysts?
Megalencephalic leukoencephalopathy with subcortical cysts is a rare genetic disease affecting the brain's white matter. People with this condition have a larger than normal head and fluid-filled pockets called cysts in the brain. It usually appears in infancy or early childhood.
Megalencephaly means an abnormally large brain. Leukoencephalopathy means disease of the white matter. Subcortical cysts are fluid-filled sacs below the brain's outer surface. In this condition, the white matter holds too much water and slowly breaks down.
Symptoms
The most noticeable early sign is a head that grows much faster than normal during the first year of life. Many children have seizures, and some have trouble with balance and movement. Over time, some develop problems with coordination or learning.
Causes and who gets it
This condition is caused by gene mutations, most often in MLC1. A child inherits it by receiving one changed gene from each parent, who are usually carriers without symptoms. It is very rare, though more common in some communities in India and Turkey.
How doctors diagnose it
Doctors measure head growth and look for a head size much larger than expected. An MRI scan shows the white matter changes and cysts. Genetic testing on a blood sample confirms the diagnosis.
Treatment
There is no cure, so treatment focuses on managing symptoms. Seizures are treated with medicines. Physical, occupational, and speech therapy can help with movement and daily skills. Doctors monitor the condition with regular checkups and brain scans.
When to see a doctor
Talk to a doctor if a baby's head seems to be growing much faster than expected, or if a child has seizures, balance problems, or delays in sitting, walking, or talking. Any seizure, especially a first one, needs prompt medical attention.
How a direct primary care or concierge doctor fits in
A direct primary care doctor is paid a flat monthly fee instead of insurance; a concierge doctor works similarly but usually charges more. They cannot replace a neurologist and would refer the patient for specialty care, but they can manage day-to-day health and help coordinate care.
Common questions
Is megalencephalic leukoencephalopathy with subcortical cysts the same as cancer?
No. It is a genetic brain disease, not cancer, and the cysts are not tumors but fluid-filled pockets.
Can adults get this condition?
Most cases start in infancy or childhood, but a milder form can appear in the teen years or adulthood, usually with milder problems with balance and thinking.
Can it be prevented?
There is no known way to prevent it, because it is inherited through genes. Families with a history of the condition can talk to a genetic counselor, who explains how genetic conditions are passed down and what testing options exist.
Will my child be able to walk?
Results differ. Some people keep the ability to walk for many years, while others lose it over time. A neurologist can give a better picture for the individual case.
Sources
- NIH Genetic and Rare Diseases Information Center - Megalencephalic leukoencephalopathy with subcortical cysts
- MedlinePlus Genetics - Megalencephalic leukoencephalopathy with subcortical cysts
Medical Disclaimer
This content is for general educational and informational purposes only and is not medical advice. It is not a substitute for professional medical advice, diagnosis, or treatment, and reading it does not create a doctor-patient relationship. Always seek the advice of your physician or another qualified health provider with any questions about a medical condition, and never disregard or delay seeking professional advice because of something you read here. If you think you may have a medical emergency, call 911 (or your local emergency number) immediately.
