Objectives: Drsal raphe from 6 male subjects with autism and 7 age- and sex-matched healthy control subjects.
Methods: We measured methylation levels of CpG sites in these samples using Infinium HumanMethylation450 BeadsChip.
Results: We found significantly elevated levels of methylation in 44 CpG-sites in 40 gene regions and significantly decreased levels of methylation in 37 CpG-sites in 34 gene regions in subjects with autism compared to controls. Some of these genes, such as DAB1 and GRIA1, have been implicated in autism and other developmental disorders (Fatemi et al., 2005; Ayalew et al., 2012). We subsequently examined to see whether modifications would be present especially on sex chromosome and altered levels of methylation were found in CpG-sites in chromosome X, but not in chromosome Y.
Conclusions: In this postmortem study, we found significant differences in DNA methylation profiles between the brains of autism and control subjects. The abnormal DNA methylations, especially gene regions implicated in autism and other developmental disorders, may underlie the pathophysiology of autism. Moreover, in sex chromosomes, abnormal DNA methylations only in X chromosome may account for the unequal sex ratio in autism.
See more of: Genetic Factors in ASD
See more of: Biological Mechanisms