To assess whether the promoter region of the serotonin transporter gene (5-HTTLPR) and G-protein β3-subunit (GNβ3 C825T) polymorphisms are associated with depressive disorder and explore the genetic mechanism concerning the pathogenesis of this disorder.
The genotypes were determined with polymerase chain reaction and allele-specific restriction enzyme analysis. Patients suffering from depression (n=184) and sex and age-matched controls (n=158) were compared in this study.
The frequencies of 5-HTTLPR SS and GNβ3 825TT genotypes and 5-HTTLPR S and GNβ3 825T alleles in patients suffering from depression were significantly higher than those in the controls (P<0.01). Combined genotype analysis showed that individuals with both 5-HTTLPR S and GNβ3 825T alleles (odds ratio=3.25, P=0.002) had a risk of depressive disorder higher than those with 5-HTTLPR S (odds ratio=1.817, P=0.01) or GNβ3 825T alleles (odds ratio=2.214, P=0.001) alone.
These results indicated that the etiology of depressive disorder is associated with 5-HTTLPR and GNβ3 C825T polymorphisms. Our data also suggests that an interaction effect may exist between the 5-HTTLPR S allele and GNβ3 825T allele in increasing the risk of depressive disorder.
aResearch Institute of Integrated Traditional Chinese and Western Medicine, Xiang Ya Hospital, Central South University, Changsha, Hunan
bDepartment of Cardiovascular Medicine, Tianjin First Central Hospital, Tianjin, P.R. China
Correspondence and requests for reprints to Dr Mei-Qun Cao, Institute of Integrated Traditional Chinese and Western Medicine, Xiangya Hospital, Central South University, Changsha 410008, Hunan, Republic of China
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Received 1 August 2006 Revised 26 October 26 2006 Accepted 15 December 2006