Effects Of The Key Genes Of 5-hydroxytryptamine Pathway On Alexithymia

Alexithymia is characterized as difficulty in identifying and describing one's own emotion.Studies showed that genetic factors influence the individual differences of alexithymia,while the mechanism of alexithymia was unclear.Studies have indicated that alexithymia is related to the availability of 5-hydroxytryptamine in the brain.In this study,the individual differences in alexithymia were investigated according to the genetypes of tryptophan hydroxylase 2 gene(TPH2),serotonin transporter gene(5-HTT),serotonin 2A receptor gene(5-HT2A),and monoamine oxidase A gene(MAOA)and the disposition of alexithymia in two dependent large samples(N1= 635;N2 = 594).Result:1.The rs4570625 and rs7305115 were selected on the TPH2 gene.The rs4570625 significantly affected the scores on TAS-20 scale(p = 0.010),the difficulty in identifying feelings(DIF;p = 0.012)and the external oriented thinking(EOT;p = 0.024),such that the individuals carrying the TT genotype showed a lower score on alexithymia of sample 1.The rs4570625 significantly affected the scores on DIF of sample 2(p = 0.05).2.The 5-HTTLPR,rs25531 and 5-HTTVNTR were selected on the 5-HTT gene.5-HTTLPR and rs25531 were combinely affected the scores on TAS-20 scale(p = 0.012),DIF(p = 0.011),and DDF(p = 0.049)in males of sample 2.3.The rs6311 and rs6313 were selected on the 5-HT2 A gene.The rs6311 significantly affected the scores on TAS-20 total(p = 0.031)and EOT(p = 0.019),such that the individuals carrying the AA genotype showed a lower disposition of alexithymia in sample 1.The rs6311 significantly affected the scores on TAS-20 scale(p = 0.024)and DIF(p = 0.019)of sample 2.The rs6313 significantly affected the scores on DDF in males of sample 1(p = 0.021),such that the individuals carrying the TT genotype showed a higher disposition of alexithymia.The rs6313 significantly affected the scores on DIF(p = 0.05).The individuals carrying the TT genotype showed a lower disposition of alexithymia of sample 2.4.The MAOAVNTR was selected on the MAOA.The results showed no significant effects on the TAS-20 total scores and three subscales(ps>0.05).Conclusion:The TPH2,5-HT2 A and 5-HTT genes in the serotonin metabolism pathway are involved in the formation of individual differences of alexithymia in normal population.