The largest clinical MRI series available was obtained from subjects participating in a multicenter study of clinical features in 48,XXYY males [Tartaglia et al., 2008]. Thirty-five of the 95 subjects had received a clinical MRI as part of evaluating conditions such as cognitive or behavioral problems, developmental delay, hypotonia, or seizures. The most common finding was nonspecific white matter abnormalities of varying extent, reported in 16/ 35 of the scans. Other findings were enlarged ventricles (8/35), agenesis of the corpus callosum (2/35), corpus callosum lipoma (3/35), cortical dysplasia (3/35), and pituitary adenoma (1/35).
