Serotonin transporter gene promoter polymorphism and alexithymia.
BACKGROUND
Recent neurobiological studies have reported that alexithymia may result from altered brain function related to emotional processing. Serotonin (5-hydroxytryptamine, 5-HT) has been shown to regulate central nervous system development associated with psychological processing. We investigated the possibility that polymorphism of the 5-HT transporter-linked promoter region (5-HTTLPR) is associated with alexithymia.


METHODS
This study included 304 healthy Japanese volunteers (148 males, 156 females). The subjects were categorized according to genotype (L/L, L/S, S/S) and results of the 20-item Toronto Alexithymia Scale (TAS-20), State-Trait Anxiety Inventory (STAI) and Self-Rating Depression Scale (SDS).


RESULTS
Subjects with the L/L genotype showed significantly higher TAS-20 scores, as well as significantly higher scores on the difficulty identifying feeling (DIF) subscale, than those with the L/S or S/S genotype (p < 0.05). There was a gender difference in the association between 5-HTTLPR genotype and DIF score. Female subjects with the L/L genotype showed significantly higher DIF scores than those with the L/S or S/S genotype (p ≤ 0.001). Neither STAI nor SDS was significantly associated with the 5-HTTLPR genotype.


CONCLUSIONS
These results suggest a link between low synaptic 5-HT and alexithymia.
Department of Behavioral Medicine, Graduate School of Medicine, Tohoku University, Sendai, Japan.
Michiko
M
Kano
Tomoko
T
Mizuno
Yuko
Y
Kawano
Masashi
M
Aoki
Motoyori
M
Kanazawa
Shin
S
Fukudo
D000328:Adult; D000342:Affective Symptoms / Q000235:genetics*; D000704:Analysis of Variance; D005260:Female; D005787:Gene Frequency; D056726:Genetic Association Studies; D020022:Genetic Predisposition to Disease / Q000235:genetics*; D005838:Genotype; D006801:Humans; D008297:Male; D011110:Polymorphism, Genetic / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000235:genetics*; D011569:Psychiatric Status Rating Scales; D050486:Serotonin Plasma Membrane Transport Proteins / Q000235:genetics*; D012737:Sex Factors; D055815:Young Adult
C493230:SLC6A4 protein, human; D050486:Serotonin Plasma Membrane Transport Proteins