Human personality traits have a considerable genetic component. Cloninger et al. were the first to postulate that certain personality traits, such as novelty seeking, are related to the dopamine neurotransmitter system. In this study, we investigated the associations between dopamine receptor D4 (DRD4) exon III and dopamine transporter (DAT1) polymorphisms and personality traits. The DRD4 and DAT1 gene polymorphisms were genotyped in 214 healthy Korean subjects, whose personality traits were assessed with the Temperament and Character Inventory (TCI). There were no significant differences between scores of TCI temperament dimensions (novelty seeking, harm avoidance, reward dependence, and persistence) and DRD4 gene polymorphism. The DAT1 gene polymorphisms also showed no significant association with any of the temperament subscales of the TCI. These data suggest that DRD4 and DAT1 gene polymorphism may not associated with personality traits in a Korean population.
Temperament ; Receptors, Dopamine D4/*genetics ; *Polymorphism, Genetic ; Personality/*genetics ; Male ; Korea ; Humans ; Female ; Dopamine Plasma Membrane Transport Proteins/*genetics ; Adult

OBJECTIVETo calculate heritabilities of personality disorders (PDs) in twin population.

METHODSBased on informed consent, we used Personality Diagnostic Questionnaire (fourth-version) as our screening tool to study the adult twins (aged 20 - 70 years) in Qingdao city. There were 324 twin pairs whose zygosity had been determined. Structural equation modeling was used to estimate the heritabilities by 242 same-sex twin pairs.

RESULTSThe best-fitting models yielded a heritability of 68.26% (60.26 - 74.78) of overall PDs, 59.00% (49.22 - 67.17) of cluster A, 64.99% (56.24 - 72.16) of cluster B, and 63.66% (54.72 - 71.02) of cluster C. There were significant genetic effects for schizotypal, narcissistic and dependent, explaining 49.96% (37.94 - 60.14), 52.89% (41.85 - 62.24) and 68.87% (60.80 - 75.40) of the variance respectively. No genetic effects were found on Histrionic, but common environmental effect accounted for 54.08% (44.50 - 62.43) of the total variances.

CONCLUSIONPD was mainly determined by genetic factor. These findings may provide evidence for future research on PD.

Adult ; Aged ; Analysis of Variance ; China ; Cluster Analysis ; Diseases in Twins ; genetics ; Environment ; Genetic Predisposition to Disease ; Humans ; Middle Aged ; Models, Genetic ; Personality Disorders ; genetics ; Personality Inventory ; Risk Factors ; Surveys and Questionnaires ; Young Adult

OBJECTIVETo study the correlation between single nucleotide polymorphism (SNP) of monoamine oxidase A gene (MAOA) and anger regulation.

METHODSEnrolled were healthy students from some college, including 225 of the high trait anger and 221 of the low trait anger. Subjects were recruited referring to the state-trait anger expression inventory 2 (STAXI-2) and their blood sampled. The DNA was extracted using phenol-chloroform method, 4 tag SNPs of MAOA (rs5906957, rs2235186, rs1181275, and rs5905613) were genotyped by PCR-based ligase detection reaction (PCR-LDR). The scores for trait anger expression inventory and the scores for trait anger expression control at the 4 tag SNPs of MAOA in the different sexes groups of the high and the low trait anger were statistical analyzed.

RESULTSThere was statistical difference in anger control score of locus rs2235186 of MAOA gene group (P = 0.037). There was no significant difference in anger expression or anger control score of different genotypes of the other three tag SNPs (P > 0.05).

CONCLUSIONMAOA gene tag SNP rs2235186 was correlated with anger control traits of healthy female college students of the low trait anger in China.

Adaptation, Psychological ; Anger ; Female ; Gene Frequency ; Genotype ; Humans ; Male ; Monoamine Oxidase ; genetics ; Personality Inventory ; Phenotype ; Polymorphism, Single Nucleotide ; Surveys and Questionnaires

There have been numerous studies on the association between 5-HTTLPR (polymorphisms in the promoter region of the serotonin transporter gene) and anxietyrelated personality traits, with conflicting results. In this study, we administered Korean version of the Temperament and Character Inventory (K-TCI) to a sample of 158 Korean college students and genotyped for the 5-HTTLPR in order to compare the TCI dimensional scores including harm avoidance according to the 5-HTTLPR genotype and sex. We could not find the association between 5-HTTLPR and harm avoidance and other TCI measures. Considering known allele frequencies differences of 5-HTTLPR among different ethnic groups, further cross-cultural studies with a larger sample would be needed.
Temperament ; Serotonin Plasma Membrane Transport Proteins/*genetics ; Personality ; Male ; Humans ; *Harm Reduction ; Genotype ; Female ; Exploratory Behavior ; Adult

OBJECTIVES: Findings from behavioral genetics which demonstrate the high heritability of personality traits have stimulated the search for the specific genes underlying personality. A large number of association studies have investigated a correlation between serotonin transporter-linked promoter region(5-HTTLPR) polymorphism and personality traits but the results have been inconsistent. So, the aim of this study is to investigate in a large sample with homogenous background about ethnicity, gender, occupation, and age. METHODS: The participants included 247 healthy Korean female adults(mean age=23.12, SD=3.22)with no history of psychiatric disorders and other physical illnesses. Genomic DNA was extracted from peripheral blood, and genotyping was performed by PCR. Personality assessment was done with the Temperament and Character Inventory(TCI). RESULTS: Genotype Frequencies are l/l 3.6%, l/s 32.8% and s/s 63.6%(l allele: 20%, s allele: 80%). This low frequency of the l allele and l/l genotype was different from Caucasian results. No significant association was observed between 5-HTTLPR polymorphism and personality traits in a Korean female population. CONCLUSIONS: This study investigated the association between 5-HTTLPR polymorphism and personality traits in Korean female subjects, a large sample with homogeneous background about ethnicity, gender, occupation, and age. No significant association was observed between 5-HTTLPR polymorphism and personality traits in a Korean female population.
Alleles ; DNA ; Female* ; Genetics, Behavioral ; Genotype ; Humans ; Occupations ; Personality Assessment ; Polymerase Chain Reaction ; Promoter Regions, Genetic* ; Serotonin* ; Temperament

OBJECTIVETo investigate the relationship between 5-HTTLPR and/or DRD4 gene polymorphisms and the accident tendentiousness of drivers.

METHODSA case-control study, including 42 patients and 46 controls, were performed using type-A behavior questionnaire and EPQ scale. 5-HTTLPR and DRD4 gene -521 C/T were detected by the PCR-RFLP technique.

RESULTSThe scores of type-A behavior questionnaires, such as TH and TH + CH in exposure group were significantly higher than those in control group (P < 0.05). P and N scores of EPQ questionnaires in exposure group were significantly higher than those in control group, and L score in exposure group was significantly lower than that in control group (P < 0.05 or P < 0.01). There were significant differences in the frequencies of the genotypes and alleles of 5-HTTLPR gene between the cases and the controls (P < 0.05), but there were no significant differences in the frequencies of the genotypes and alleles of DRD4 gene between the two groups (P > 0.05). In the drivers with the accident tendentiousness, P scores in the cases with homozygous genotypes of the S/S in 5-HTTLPR gene were significantly higher than those in the cases with the genotypes of S/L and L/L in 5-HTTLPR gene (P > 0.05). E scores in subjects with homozygous genotypes of the T/T in DRD4 gene were significantly higher than those in subjects with genotypes of the T/C+C/C in DRD4 gene (P > 0.05).

CONCLUSIONThe driver accident tendentiousness may be associated with 5-HTTLPR gene, but not associated with DRD4 gene. The two genes are associated with the type-A behavior and personality characteristics of drivers with accident tendentiousness. However, 5-HTTLPR and DRD4 gene may not have synergism in these behaviors and personality.

Accidents, Traffic ; statistics & numerical data ; Adult ; Automobile Driving ; Case-Control Studies ; Genotype ; Humans ; Male ; Personality ; genetics ; Polymorphism, Genetic ; Receptors, Dopamine D4 ; genetics ; Serotonin Plasma Membrane Transport Proteins ; genetics