关键词: 孤独症谱系障碍, ENO2基因, 神经发育, 甲基化, 表观遗传

Abstract: Objective To explore the methylation modification of ENO2 gene in peripheral blood of children with autism spectrum disorder (ASD),in order to provide theoretical evidence for early screening of ASD. Method Peripheral blood from ASD children and control children were collected to analyze differential methylation by methylated-DNA immunoprecipitation (MeDIP) chips. One neuron-specific gene,ENO2,was found to be hypermethylated in the autistic samples. In addition,obtained blood samples were collected from 101 autistic children and controls matched with age and sex. This difference was validated by bisulfite sequencing PCR (BSP). The differential expression of ENO2 gene was further analyzed by real-time quantitative polymerase chain reaction (RT-qPCR) and ELISA. Results The hypermethylation of ENO2 within the promoter region was confirmed by BSP to be present in 15.8% (16/101) of the autistic samples. The methylation frequency of 16 CpG sites of ENO2 gene promoter was calculated,and it was found that the closer the promoter was to the start site of transcription,the higher the methylation frequency would be. The mean level of ENO2 RNA in these 16 autistic samples was reduced by 30% approximately compared with that in controls. The average level of ENO2 protein expression in 16 autistic samples was (15.15±3.52) μg/L,about half of that in the controls[ (33.78±8.18) μg/L]. Conclusions Hypermethylation of ENO2 gene is found in peripheral blood of 15.8% of ASD children. Moreover,reduced level of ENO2 expression may be a biomarker for a subset of autistic children.

Key words: autism spectrum disorder, ENO2 gene, neurodevelopment, methylation, epegenetics