Significance of serotonin transporter gene polymorphism in tinnitus.
OBJECTIVE
To assess the role of serotonin transporter gene (SLC6A4) polymorphism in tinnitus.


METHODS
Fifty-four consecutive patients experiencing subjective tinnitus and 174 healthy controls were allocated for the study. Psychoacoustic parameters of tinnitus were measured. Beck Depression Inventory was used to assess the depression level of the patients. Tinnitus Handicap Inventory was used to assess the severity of tinnitus. A visual analog scale was designed to measure the impact of tinnitus on quality of life of the patients. The 44-bp insertion-deletion in the promoter region (5-HTTLPR) and 17-bp variable number tandem repeats in the second intron of the serotonin transporter gene were assessed.


RESULTS
No difference was found between the genotypes and allele frequencies of the patients and controls regarding variable number tandem repeats and 5-HTTLPR polymorphisms (p > 0.05). There was no association between the psychoacoustic parameters of tinnitus and SLC6A4 polymorphism (p > 0.05). There was a significant association between the 5-HTTLPR polymorphism and scores from the visual analog scale of the patients (p < 0.05).


CONCLUSIONS
Generation of tinnitus signal is not associated with SLC6A4 polymorphism and possibly with serotonergic mechanisms. However, the "ll" genotype variant of the SLC6A4 polymorphic promoter region seems associated with the limbic and autonomic nervous system symptoms of the patients with tinnitus. Therefore, serotonergic mechanisms may help explain the neurophysiological model of tinnitus, and serotonin replacement or serotonin reuptake inhibitors may increase the success rate of tinnitus treatment modalities based on the neurophysiologic model of tinnitus.
Deniz
Murat
M
Department of Audiology, Faculty of Medicine, Gazi University, Besevler, Ankara, Turkey.
Bayazit
Yildirim A
YA
Celenk
Fatih
F
Karabulut
Hayriye
H
Yilmaz
Akin
A
Gunduz
Bulent
B
Saridogan
Cagil
C
Dagli
Muharrerm
M
Erdal
Emin
E
Menevse
Adnan
A
D000328:Adult; D000483:Alleles; D000704:Analysis of Variance; D001301:Audiometry, Pure-Tone; D016009:Chi-Square Distribution; D005260:Female; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease / Q000235:genetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D018579:Patient Selection; D016133:Polymerase Chain Reaction; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D011569:Psychiatric Status Rating Scales; D011788:Quality of Life; D012701:Serotonin / Q000235:genetics*; D050486:Serotonin Plasma Membrane Transport Proteins / Q000235:genetics*; D012720:Severity of Illness Index; D014012:Tinnitus / Q000235:genetics*; D018911:Trinucleotide Repeats / Q000235:genetics
D050486:Serotonin Plasma Membrane Transport Proteins; D012701:Serotonin