MLC1 and megalencephalic leukoencephalopathy with subcortical cysts: Megalencephalic leukoencephalopathy with subcortical cysts (MLC) is a rare type of leukodystrophy (OMIM 604004) mainly caused by mutations in the MLC1 gene (MIM #605908) (Leegwater et al., 2001; Topçu et al., 2000).