Abstract：Objective To determine the methylation level of genomic DNA in patients with autism spectrum disorder (ASD), and to explore its significance in the pathogenesis of ASD. Methods We collected peripheral venous blood samples from 30 ASD patients and 20 healthy controls in Department of Child Health Care, Hunan Children’s Hospital from January, 2014 to February, 2016. Peripheral blood mononuclear cells (PBMCs) were isolated, and DNA was extracted with Tiangen Genomic DNA kit. The global genomic DNA methylation levels in PBMCs were measured through commercial kit. The mRNA expression levels of DNA methyltransferase 1 (DNMT1) were detected by real-time quantification PCR. And the correlation between global DNA methylation level and DNMT1 mRNA as well as their correlation with the scores of Autism Behavior Checklist (ABC) were analyzed. Results The global DNA methylation level in PBMCs in the ASD patients was significantly lower than that of the healthy controls, with a statistically significant difference (P<0.05). No staitistically signicant difference was found in the expression of DNMT1 mRNA between the ASD patients and the healthy controls (P>0.05). There was no obvious correlation between the expression of global DNA methylation and the expression of DNMT1 mRNA (r=0.311, P=0.182) in the ASD patients, but the global methylation level was negatively correlated with the scores of ABC in the ASD patients (r=-0.504, P=0.038). No significant correlation was observed between the expression level of DNMT1 mRNA and the scores of ABC(r=-0.112, P=0.645). Conclusions The global genomic DNA methylation levels of the ASD patients are deceased.
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2017, Vol. 24 
