Fig. 2
Examples of white and grey matter changes. a Mild, predominantly periventricular white matter changes (arrows) in control patient c1. b Focal and confluent, slightly asymmetrical white matter changes as well as mild periventricular white matter hyperintensity (arrows) in late-onset patient p5. c, d Extensive white matter changes in late-onset patient p1 at 8.5 (c) and 15.7 years (d) with slight progression during follow-up (e.g. temporal, arrows d, compare with c). NB T2-hyperintensity of pallidum and medial thalamus is only depicted at follow-up (d, arrow to right thalamus) due to different slice angulation of examinations. e, f Extensive white matter changes in control patient c6 without progression between 11 (e) and 19 years (f) involving periventricular, lobar, and subcortical white matter. Pattern of involvement is similar to p1 with a rim of near normal signal (arrows) interspersed between changes of periventricular and more peripheral white matter. g, h. White and grey matter changes in late-onset patient p7 at the age of 61 (g) and 73 years (h). At the age of 61 years there is a combination of mild, periventricular and multiple, brighter white matter hyperintensities undistinguishable from hypertensive white matter changes observed in non-GA1-patients at this age. Subacute ischemia of the right dorsolateral medulla oblongata (arrows in g 1,2), which was the cause of the acute neurological presentation, retracts over time (arrow in h 1) as does the pre-existing anterior lenticular and caudate defect (arrow in g 4, compare with h 4). By the age of 73 years, white matter changes have increased. Bilateral occipital (arrows in h 2,3, compare with g 3) and hemodynamic ischemia in the left parietal border zone (arrows in g 4,5) have left defects and gliosis and there is overall volume loss with widening of ventricles and sulci. (T2w: a-f, g 2, h 1; FLAIR: g 1, g 3–6, h 2–6)