ABSTRACT
<p><b>OBJECTIVE</b>To investigate the association between dopamine D4 receptor gene DRD4 exon III 48bp variable number of tandem repeat (VNTR) polymorphism and temperament in school-aged children.</p><p><b>METHODS</b>Randomized cluster sampling was used to select 350 healthy children aged 8-12 years, and a questionnaire survey was performed. Oral epithelial samples were collected from half of these children. The complete questionnaire data of 164 children with a high level of DNA in oral epithelial samples were included in this study. PCR was used for the typing of DRD4 exon III 48bp VNTR, and the effect of this gene and its interaction with the environment on temperament was analyzed.</p><p><b>RESULTS</b>Compared with the children with S-DRD4 genotype, the children with L-DRD4 genotype had significantly lower scores on the four dimensions of activity level, reaction intensity, emotion essence, and persistence (P<0.05). The main effects of mother's rejection/denial (OR=2.281, P<0.05) and sex (OR=2.766, P<0.05) and the interaction between sex and DRD4 exon III 48bp VNTR (OR=0.582, P<0.05) had an influence on activity level. The main effect of DRD4 exon III 48bp VNTR (OR=0.314, P<0.01) and the interaction between this gene and mother's rejection/denial (OR=1.872, P<0.01) had an influence on reaction intensity. The main effect of DRD4 exon III 48bp VNTR (OR=0.420, P<0.05) and mother's rejection/denial (OR=2.236, P<0.05) had an influence on persistence.</p><p><b>CONCLUSIONS</b>DRD4 exon III 48bp VNTR and its interaction with other factors may affect the activity level and reaction intensity of school-aged children.</p>
ABSTRACT
<p><b>OBJECTIVE</b>To study the effects of rs4274224 polymorphisms in the DRD2 gene, family factors and their interaction on the regularity in school-age children.</p><p><b>METHODS</b>The rs4274224 polymorphisms were genotyped using Sequenom Mass Array. The regularity was assessed based on the Middle Childhood Temperament Questionnaire (MCTQ). The parental rearing pattern was assessed with Egna Minnen av Bardnodnauppforstran (EMBU). The family function was assessed using Family Cohesion and Adaptability Scale (FACES II-CV).</p><p><b>RESULTS</b>The regularity score in children with AA genotype of rs4274224 in the DRD2 gene was significantly lower than in those with GA/GG genotype (2.9±0.6 vs 3.1±0.7; P<0.05). The results of multiple regression analysis showed that the regularity was related to child gender, father's education level and family adaptability. The results of logistic regression analysis showed that the main factors influencing the regularity were family adaptability and its interaction with rs4274224 polymorphisms. The regularity was better in children with high family adaptability than in those with low family adaptability (OR=0.112, P<0.01). The children with AA genotype and low family adaptability were tend to be associated with low regularity (OR=21.554, P<0.01).</p><p><b>CONCLUSIONS</b>The regularity based the temperament for school-age children might be influenced by family adaptability and its interaction with rs4274224 polymorphisms.</p>