Figure 2.

Neuroimaging results in patient 1. (a–d) MRI age 18 months: T1W sagittal image (a) shows a thin corpus callosum with the lack of isthmus and a tapered splenium (arrow). The optic chiasm is atrophied or hypoplastic. T1W axial image (b) demonstrates age-appropriate gyral development and mild delay in juxtacortical myelin maturation. T2W axial (c) and coronal (d) reveals prominence of the lateral ventricles, particularly anteriorly. There is flattening of the lateral walls of the frontal horns (arrow). Anterior pericerebral space is increased. (e–h) MRI age 6 years 10 months: T1W sagittal image (e) shows that corpus callosum remains thin, with a tapered splenium and with a lack of isthmus. The chiasm remains significantly small (arrow). MRS TE 144 (f) performed in the basal ganglia shows age-appropriate spectra. T2W axial images (g and h) reveal that myelin maturation is now age appropriate, although the white matter is thinned. The ventricles, in particular the anterior horns, remain prominent with flattening of the lateral walls (arrow).