The largest 49,XXXXY imaging case series to date included three individuals studied at different ages [Hoffman et al., 2008]. One subject who underwent MRI for significant developmental delay was scanned at 14 months of age and again at 20 months. Both exams were significant for decreased brain volume, increased ventricular volume, and decreased width of the corpus callosum. T2 images also showed widespread bilateral patchy and confluent areas of abnormal high signal intensity, particularly in the periventricular and deep white matter of the parietal and frontal lobes. The second subject was scanned at 7 years of age. He also had volume loss, enlarged ventricles, and thinning of the corpus callosum. Periventricular and subcortical white matter showed several puncate foci of increased signal intensity. The third case was an adult of 39 years, who underwent MRI following the development of generalized tonic-clonic seizures. Findings included volume loss and atrophy in both cerebrum and cerebellum, associated with increased ventricular volume and thinning of the corpus cal-losum. The greatest volume loss was seen in the parietal lobes. Multiple foci of increased signal intensity
