APOE Hypermethylation Is Associated With ASD In Chinese Population

ObjectiveApolipoprotein E(APOE)could produce a glycoprotein that was related to li poproteins.Abnormal methylation of APOE was associated with Alzheimer’s disea se(AD),which may have overlapping mechanisms with ASD.Genetic study indicate d that APOE variant was associated with ASD,however,its remained unknown whe ther APOE methylation was linked to ASD.According to previous experimental re sult,We planed to make out whether ASD associated with Apoe methylation through this research.Methods We acquired 135 blood samples,experimental group was 62 ASD children and con trol group was 73 healthy children,they all came from Ningbo Kangning Hospital in Ningbo city of Zhejiang province,China.For accurate diagnosis of ASD,both t he Diagnostic and Statistical Manual for Mental Disorders,IV Edition and 2 Sca les(he ASD behavior checklist and the Childhood Autism Rating Scales)were app licated by us.Blood samples were drawn from healthy controls and ASD cases prio r to treatment.pregnant history,family history and so on all were the relevan t clinical data we had collected.After both Ningbo Kangning Hospital’s Ethics Committee and the parents of all the children had assessed and approved,the st udy could be conducted.The organization that was used to extract DNA was peripheral blood and the vol ume of peripheral blood was 2ml.After the DNA was bisulphite converted,quanti tative methylation-specific PCR(qMSP)was used for the current methylation ass ay of APOE.The software we analyzed the results and data was the SPSS software version 18.0.Independent sample T test was applied for the comparisons of APOE methylation differences between ASD cases and controls.Of course,the diagnos tic value of APOE methylation need to be evaluated,receiver operating characte ristic curves just could solve this problem.Spearman rank test was applied to assess the associations between APOE methylation and clinical indicators in ASD.P <0.05 indicated that there was a statistically significant difference.ResultsOur results showed that APOE methylation was significantly higher in ASD ch ildren than healthy controls(median PMR: 33.36% versus 10.61%,P = 2.36E-10).In consideration of a strong potential link between the gender differences and ASD,so it is necessary to study with genders.Our results showed that the rela tive APOE methylation level of males was much higher in case groups than contro l groups(median PMR: 32.12% versus 11.00%,P = 8.51E-7).At the same time the relative APOE methylation level of females was much higher in case groups than control groups(mean PMR: 43.35% versus 7.87%,P = 4.18E-6,).In addition,we assessed the diagnostic ability of APOE methylation by ROC curve analysis.The specificity was 72.6% and the sensitivity was 93.5%,the ar ea under curve(AUC)was 0.817(95% CI: 0.741-0.893),P = 2.36E-10.Through subgroup analysis by gender we could find that a similar result in males existed(specificity: 67.7%,sensitivity: 93.9%,AUC = 0.773,95% CI: 0.682-0.865,P = 8.52E-7).Because the number of female individuals was finite,we were unable to carry out ROC curve analysis in females.Conclussionour study showed that APOE hypermethylation was associated with ASD.Next s tudy will seek that APOE hypermethylation of the DNA in peripheral blood is a d iagnostic marker for ASD.