The study of the magnetic resonance pattern allowed for identification and description of many genetic disorders belonging to a group of non-specific leukodystrophy e.g. leukoencephalopathy with macrocephaly and mild clinical course (van der Knaap syndrome, MLC megalencephalic leukoencephalopathy with subcortical cysts). This leukodystrophy is characterized by macrocephaly in the first year of life, initially normal development, progressive neurological dysfunction and preservation of mental abilities. The authors describe 3 new cases of vacuolating leukoencephalopathy with megalencephaly. The presented patients fulfill the clinical and neuroimaging criteria of van der Knaap syndrome.