There are a few case reports of brain imaging results of individuals with more than two Y-chromosomes. CT scan results were reported in a 22-year-old nonmosaic 49,XYYYY male who appeared to be having moderate to severe intellectual disability. Although he had normal head size in the 75th centile, CT scan results showed bilateral ventricular enlargement and diffuse cortical atrophy [Shanske et al., 1998]. A postmortem report from a 28-week-old 49,XYYYY fetus also found abnormalities, including a hypoplastic corpus callosum and a small cerebellum with a large cyst [Frey-Mahn et al., 2003]. By contrast, CT scans in other young 49,XYYYY males, including a 14 month old [Sirota et al., 1986] and a 28 month old [DesGroseilliers et al., 2002], were reported as normal.
