Megalencephalic Leukoencephalopathy with Subcortical Cysts (MLC1)
Megalencephalic leukoencephalopathy with subcortical cysts is an autosomal recessive disease caused by pathogenic variants in the gene MLC1. The clinical presentation is variable but most commonly begins with delayed walking and low muscle tone. Motor function worsens over time, and most affected individuals are wheelchair-bound by late childhood. This condition causes seizures and difficulties in school. Affected individuals have larger than average heads. The effect on life expectancy is not known due to its relatively recent discovery. It is known that some affected individuals have passed away in their teens or twenties, while others have lived into late adulthood. It is not currently possible to predict how severe the disease will be based on the type of inherited variants. This disease can affect people of any ethnicity, but it is more common in people who are Libyan Jewish.
For information about carrier frequency and residual risk, please see the residual risk table.