Association Analysis Between 12 Genetic Variants of Ten Genes and Personality Traits in a Young Chinese Han Population

Variations in 5-HT2A Influence Spatial Cognitive Abilities and Working Memory

Background:

5-hydroxytryptamine receptor 2A (5-HT2A) participates in diverse psychiatric disorders by regulating the activity of serotonin. Some previous studies have also suggested that the receptor is involved in cognitive abilities of disease groups. We hypothesize that some functional genetic variants in 5-HT2A have certain specific influences on cognitive abilities in a normal population.

Method:

To confirm this hypothesis, two polymorphisms (rs6313 and rs4941573) in 5-HT2A were selected, and a population-based study was performed in a young healthy Chinese Han cohort.

Results:

The results indicated that the rs6313 and rs4941573 were associated with touching blocks and mental rotation-3D error ratio in males, and the rs4941573 was associated with visuo-spatial working memory in the whole cohort.

Conclusion:

All the findings suggest that 5-HT2A participates in human spatial cognitive abilities and spatial working memory.

Synergistic effects of COMT and TPH2 on social cognition

Whether genetic factors affect social cognition, particularly emotion management, requires elucidation. This study investigates whether social cognition varies with genetic variations of COMT and tryptophan hydroxylase-2 (TPH2), which modulate dopamine and serotonin neurotransmissions respectively, and thereby emotion regulation. NIMH-recommended "managing emotions branch and 2 subtasks" of MSCEIT and six neurocognition domains, and genotypes of COMT Val158Met and TPH2 G703T were measured in 150 Han-Chinese healthy adults. Subjects carrying the M allele (M group) of COMT exceeded Val/Val homozygotes (V group) in managing emotions branch (p = 0.032) and emotional relation subtask (p = 0.037). TPH2 T/T homozygotes (T group) excelled those with the G allele (G group) in emotional management subtask (p = 0.025). Subjects with M+T variation surpassed the other 3 groups (M+G, V+T and V+G) in managing emotion branch (p = 0.002), emotional relation subtask (p = 0.023), and emotional management subtask (p = 0.002). The findings remained after control for gender, age, education, and neurocognitive functions. Synergistically, the effect size of COMT-TPH2 combination surmounted the sum of separate effect sizes of COMT and TPH2. The findings suggest that genetic variations of COMT and TPH2 have synergistic effects on social cognition in the general population.

Polymorphisms in ABLIM1 are associated with personality traits and alcohol dependence

Personality traits like novelty seeking (NS), harm avoidance (HA), and reward dependence (RD) are known to be moderately heritable (30-60%). These personality traits and their comorbidities, such as alcohol dependence (AD), may share genetic components. We examined 11,120 single nucleotide polymorphisms (SNPs) genotyped in 292 nuclear families from the Genetic Analysis Workshop 14, a subset from the Collaborative Study on the Genetics of Alcoholism (COGA). A family-based association analysis was performed using the FBAT program. NS, HA, and RD were treated as quantitative traits and AD as a binary trait. Based on a multivariate association test of three quantitative traits in FBAT, we observed 20 SNPs with p < 10(-3). Interestingly, several genes (TESK2, TIPARP, THEMIS, ABLIM1, RFX4, STON2 and LILRA1) are associated with three personality traits with p < 10(-3) using single trait analysis and AD. Especially, SNP rs727532 within ABLIM1 gene at 10q25 showed the most significant association (p = 6.4 × 10(-5)) in the multivariate test and strong associations with NS, HA, RD, and AD (p = 4.48 × 10(-4), 1.2 × 10(-5), 5.6 × 10(-5), 3.12 × 10(-4), respectively) in the COGA sample. In addition, the association of rs727532 with AD was confirmed in a replication study. This study reports some newly recognized associations between several genetic loci and both AD and three personality traits.

Association analysis of TPH2, 5-HT2A, and 5-HT6 with executive function in a young Chinese Han population

The 5-hydroxytryptamine (5-HT) system is widely distributed in the central nervous system. A growing body of evidence has suggested that the neurotransmitter system is implicated in the functions of the prefrontal cortex. So far, several studies have revealed that some functional genetic variants in TPH2, 5-HT2A, and 5-HT6 genes are possibly related to executive function. To investigate the potential influences of TPH2, 5-HT2A, and 5-HT6 on the components of executive function, the authors performed a population-based study with standard cognitive paradigms in a young Chinese Han group. The results indicated that -703 G/T polymorphism of TPH2 was associated with the performance of response inhibition (p = .002) and the T allele carriers (TT and GT) had fewer errors than the noncarriers (GG) did in the response inhibition test. Furthermore, there were no significant associations of the T102C in 5-HT2A and T267C in 5-HT6 with the components of executive function after correcting for multiple tests (p > .05). The present study suggests that TPH2 contributes distinctively to the inhibition domain of executive function, whereas 5-HT2A and 5-HT6 show no striking effects on executive function in the Chinese Han population.

No observable relationship between the 12 genes of nervous system and reasoning skill in a young Chinese Han population

Reasoning skill is an advanced cognitive ability which is needed for drawing inferences from given information. It is well known that the ability depends on the neural network of the frontal and parietal brain regions. In this study, we hypothesized that some genes involved in neurotransmitter systems were related to reasoning skill. To confirm this hypothesis, we examined the effects of 13 genes (BDNF, NRSF, COMT, DBH, DRD(2), DRD(3), DAT(1), MAOA, GRM(1), GRIN2B, TPH(2), 5-HT(2A), and 5-HT(6)) in neurotransmitter systems on the non-verbal reasoning and verbal reasoning skills. The results indicated there were on significant effects of the 17 functional variants of these genes on the performance of non-verbal reasoning and verbal analogical reasoning skills (χ(2) > 3.84, df = 1, P > 0.05). This study suggests that some of the functional variations in BDNF, COMT, DBH, DRD(2), DRD(3), MAOA, 5-HT(2A), 5-HT(6), GRM(1), and GRIN2B have no observable effects on the certain reasoning skills in a young healthy Chinese Han population.