Association Between Genetic Variations Of SNARE Complex Gene And Attention-deficit/Hyperactivity Disorder

Part1 The genetic variations of SNARE complex gene with susceptibility to ADHDObjective:To investigate the genetic variations of SNARE complex gene associated with the susceptibility and clinical symptoms of ADHD in children so as to provide novel thought and theoretical basis for the pathogenesis of ADHD.Methods:A case-control study was performed among Southern Han Chinese including754 cases and 772 controls from two Hunan and Wuhan.The inclusion criteria of the participants were as follows:（1）age 6-18;（2）the intelligence test of Chinese-Wechsler Intelligence Scale for Children was more than 70 points.The cases were new medication-free cases diagnosed by Swanson,Nolan,and Pelham-IV Questionnaire（SNAP-IV）,and children with neurological disorders,pervasive developmental disorders,bipolar disorders,seizure disorders,or psychotic disorders were excluded.The controls were healthy children conducted physical checkups during the same period and there was no history of ADHD or other family history of psychiatric disorders.SNAP-IV,Parent Symptom Questionnaire（PSQ）and Integrated Visual and Auditory Continuous Performance Test（IVA-CPT）were conducted to evaluate the clinical features of all subjects.We selected candidate genes and SNPs by utilizing multiple bioinformatics tools（including NCBI-SNP,SNPinfo,HaploReg,rSNPBase and Regulome DB）and combining previous GWAS and candidate gene studies.Genotyping of candidate SNPs were performed using the Sequenom MassARRAY.The differences between cases and controls in the distribution of demographic characteristics and genotypes were analyzed with Pearsonχ² test or t-test.Logistic regression analysis was performed to analyze the association between SNPs and ADHD risk.The differences of clinical features among genotypes were explored by ANOVA.Besides,Bonferroni correction was performed for multiple comparisons.Results:1.With the Bonferroni correction,the results of association analysis showed that SNAP-25-rs3746544,STX1A-rs3793243 and STX1A-rs875342 were all significantly associated with ADHD.rs3746544 was relative to ADHD in HV vs.HW model（OR=1.605,95%CI=1.107-2.315）and addictive model（OR=1.502,95%CI=1.019-2.213）.rs3793243 was relative to ADHD in HV vs.HW model（OR=0.564,95%CI=0.406-0.692）,recessive model（OR=0.668,95%CI=0.498-0.836）and addictive model（OR=0.792,95%CI=0.674-0.912）.rs875342 was relative to ADHD in HV vs.HW model（OR=1.806,95%CI=1.349-2.591）.2.SNAP-25-rs3746544 was associated with hyperactive/impulsive score and hyperactive index（P<0.005,respectively）.STX1A-rs3793243 and STX1A-rs875342were implicated in attention-deficit score（P<0.005,respectively）.Conclusions:SNAP-25-rs3746544,STX1A-rs3793243 and STX1A-rs875342 were associated with the susceptibility and clinical symptoms of ADHD in children.Part2 The effects of SNARE complex genetic variations interaction with gene and environmental factors on ADHD susceptibilityObjective:To evaluate the roles of gene-gene（G′G）and gene-environment（G′E）interactions in ADHD.Methods:A self-designed questionnaire was used to investigate environmental factors of all subjects.Blood lead level（BLL）was evaluated using atomic absorption spectrometry.Univariate and multivariate logistic regression analysis were performed to analysis the association between environmental factors and ADHD.Besides,logistic regression model,decision tree and multiple factor dimensionality reduction（MDR）were used to analyze the G′G and G′E of the genetic variation associated with ADHD risk,and evaluate the effect of interactions on ADHD risk.Results:1.G′G analysis showed that there were significant multiplicative and additive interactions between SNAP-25-rs3746544 and STX1A-rs3793243.Children carry both rs3746544（GT/TT）and rs3793243（AG/AA）genotypes had 1.937 times more risk to suffer ADHD than those who carry rs3746544（GG）and rs3793243（GG）genotypes(P_mul=0.011,OR=1.937,95%CI=1.325-2.832,P=0.001).The risk was attributed to the interaction of the two factors,accounting for 26.6%（API=0.266,95%CI=0.035-0.497）.2.Univariate and multivariate logistic regression analysis indicated that maternal stress（OR=1.466,95%CI=1.032-2.082）and BLL（OR=1.370,95%CI=1.112-1.689）were risk factors for ADHD.3.Decision tree and MDR suggested that STX1A-rs3793243 significantly interacted with maternal stress and BLL,and this n-factor G′E increased ADHD risk by 79.3%（OR=1.793,95%CI=1.452-2.213,P<0.001）.Two-factor G′E analysis achieved by logistic regression indicated that there were significant multiplicative and additive interactions between three positive SNPs（SNAP-25-rs3746544,STX1A-rs793243 and STX1A-rs875342）and two positive environment factors（maternal stress and BLL）.Conclusions:SNAP-25-rs3746544 interplayed with STX1A-rs3793243 to modify ADHD susceptibility.Maternal stress and high BLL were environmental risk factors of ADHD.There were significant n-factor and two factor G′E among maternal stress,BLL and STX1A-rs3793243 to modify ADHD susceptibility.