GCSAML and Klinefelter syndrome: We notice that a significant change toward a hypermethylated status at four CpG sites (β differences ranged from +0.15 to +0.22) within the chromosomal region corresponding to the GCSAML secondary maternal iDMR has been reported in postmortem prefrontal cortex in one case of Klinefelter syndrome (47,XXY karyotype) versus control males (Viana et al., 2014), and the perturbation was subsequently confirmed in a second study using venous blood samples from five patients with Klinefelter syndrome (Wan et al., 2015).