An Association Study Between DRD2 Gene Polymorphism And Behavioral Problems In School-age Children

Psychological behavioural problems in children are abnormal behaviours that exceed the normal range in severity and duration.Risk factors for behavioural problems in children include many factors such as biology,family environment and psychosocial.In order to understand the factors influencing the psychological behavior of school-age children,this study adopted a whole-group random sampling method to select 500and 450 Mongolian and Han Chinese children aged 8-12 years old,respectively,in Arukorqin Banner,Chifeng City,Inner Mongolia,the Achenbach Child Behaviour Inventory（ACBI）was used to measure various factors of children’s psychological behaviour,and the Carey Standardised Temperament Questionnaire（MCTQ）,the Chinese Standardised Test of Child and Adolescent Psychological Development（CSCAPD）scale,the Adolescent Life Events Scale（ALES）and the General Family Situation Questionnaire（GFSQ）were used to investigate children’s temperament,parenting styles,life events and family life environment,The whole genomic DNA of children’s oral epithelial cells was extracted using the TIANamp Swab DNA Kit,the DRD2 gene Taq1A was amplified by PCR amplification technique,Taq1A genotyping was performed using restriction endonuclease Taq1,and rs6278,rs6279,rs1799978,rs1801028 were typed by i MLDRTM technique.Theχ~2test,independent samples t-test,ANOVA,binary logistic regression,multiple linear regression,and general linear model were used to analyse the factors influencing psychological behavioural problems,and Haploview4.2 was used to analyse the five single nucleotide polymorphism（SNPs）loci were tested for linkage disequilibrium.The results found that:（1）The overall detection rate of behavioural problems among Han Chinese schoolchildren was 10.76%（12.28%for males and 9.09%for females）,with the highest detection rate of anxiety and depression（8.00%）and the second highest of introversion（7.55%）among the individual behavioural problems.The lowest detection rate was for withdrawal behavioural problems（0.00%）;the overall detection rate for Mongolian school-age children was 34.81%（35.22%for males and 34.39%for females）,with the highest detection rate for introversion among individual behavioural problems（29.05%）;the second highest was for thinking problems（22.62%）;the lowest detection rate was for attention problems（2.00%）,and socialization problems had gender differences and a higher detection rate for boys（10.87%）than for girls（4.98%）.（2）The main factors influencing children’s psychological behavioural problems include temperament type,age,gender,parental occupation,parental education,the occurrence of major events,the presence of illness during pregnancy,mode of delivery and the child’s primary caregiver and parenting style,where the interaction between father’s authoritarian parenting style and temperament type has an effect on children’s anxiety and depression,introverted behaviour,extroverted behaviour,father’s authoritarian parenting style and its interaction with maternal occupation and other factors on introverted and extroverted behaviour,respectively,the interaction of maternal authoritarian parenting style with temperament type on socialising behaviour and total behavioural problems,and the interaction of maternal authoritarian parenting style with loss factor and interpersonal relationship factor on socialising behaviour and total behavioural problems,respectively.Partial or full mediating effects of the nine dimensions of child temperament in the influence of environmental factors on behavioural problems in school-age children.（3）Taq1A was associated with the occurrence of introverted behavior problems,anxiety and depression,and disciplinary behavior scores of children;the interaction with age had an effect on the occurrence of introverted behavior in Mongolian children,the interaction with authoritarian and permissive parenting style had an effect on disciplinary behavior scores of Han children,and the interaction with gender and parental education had an effect on disciplinary scores of Mongolian children（p<0.05）;rs1799978 was associated with the occurrence of socialization problems and extraverted behavior problems,and the interaction with easy-parenting type had an effect on the extraverted behavior of Han children,and the interaction with gender and age had an effect on the socialization and extraverted behavior of Mongolian children,respectively（p<0.05）.This study concludes that（1）Qualitative psychological and behavioral problems are mainly affected by temperament type,parents’educational level,parents’occupation and whether they are full-term.Introverted behavior problems are affected by Taq IA,and socialized and extroverted behavior problems are affected by rs1799978;Quantitative behavior problems are mainly affected by gender,temperament type,parents’occupation,parents’education level,parents’upbringing style and other factors.Taq IA has an impact on anxiety,depression and discipline violation scores.（2）Family environment can act not only directly on child behavioural problems,but also indirectly through temperament.Temperament may play a mediating role in child environmental factors and child psychological behavioural problems,and this study found that nine dimensions of temperament had partial or complete mediating effects in the influence of environmental factors on school-age children’s behavioural problems.This suggests that parents should educate their children according to their children’s temperament as well as focusing on the influential role of the home environment in the process of raising their children.（3）This study suggests that genes and environment jointly influence children’s psychological behavioural problems,and that the interaction between Taq IA,rs1799978 and the environment has an effect on school-age children’s psychological behavioural problems.