Pattern B1: MR images of a ‚later onset‘patient. Patient 34 (onset 5 years, age at MRI 5 years 1 month). White matter is primarily affected in the periventricular parieto-occipital regions (arrows in the upper right Flair image, and lower left sagittal and lower right T2w images). The Flair image shows the involvement of the splenium of the corpus callosum (black arrow). Cerebellar white matter is not affected (axial T2w image upper left).