Association Study for a Functional Serotonin Transporter Gene Polymorphism and Late-Onset Alzheimer’s Disease for Chinese Patients

Abstract

Two recent studies have demonstrated an association for a deletion/insertion polymorphism within the promoter region of the serotonin transporter gene (5-HTTLPR), and Alzheimer’s disease (AD). According to these studies, subjects with the short variant of the 5-HTTLPR gene are at increased risk for AD; however, this finding has not been confirmed by other workers. To evaluate the role of the 5-HTTLPR gene in susceptibility for AD, we conducted an association study for this polymorphism in a Chinese population. No significant differences were determined for genotype distribution or allele frequencies, comparing AD patients and normal controls. Even dividing the population into subgroups according to the presence of the APOE Ε4 allele, no differences for genotype or allele frequencies were determined, comparing patients and controls. These results suggest that it is unlikely that the 5-HTTLPR polymorphism plays a substantial role in conferring susceptibility to AD.

Evaluating Associations between 5-HTTLPR Polymorphism and Alzheimer’s Disease for Korean Patients

“…These results suggested that the association between 5-HTTL-PR polymorphism and AD might vary according to the different ethnicities. The s allelic frequency in this study sample (73-75%) was similar to the results of other studies with Asian populations (72-80%) [8,10] , but it was much higher than those from the studies with Caucasian populations (40-50%) [5][6][7] . If the s allele is a risk factor for AD, the prevalence of AD should be higher in Asian populations.…”

“…A striking feature of research on the association between 5-HTTLPR polymorphism and AD was the confl icting fi ndings according to the sampled populations. Studies conducted in England [5] , Brazil [6] and Germany [7] reported signifi cant associations, while others from Japan [8] , Germany [9] and China [10] found no associations. Two of the 3 studies reporting the negative fi ndings were based on oriental populations, which was in keeping with the result of the present study with Koreans.…”

“…However, studies on the association between the s allele and AD have failed to demonstrate consistent results. Some reported a signifi cant association [5][6][7] , while others found no evidence to support such a generalization [8][9][10] . The results of the previous studies have shown a particular tendency that studies with Caucasian populations reported positive fi ndings, while most studies with Asians reported negative ones.…”

Serotonin transporter and tryptophan hydroxylase gene polymorphisms in Chinese patients with generalized anxiety disorder

“…Genotype frequencies in both groups were in Hardy-Weinberg equilibrium. The frequency of short allele in healthy subjects (71%) was similar to that reported in other Chinese population (Tsai et al, 2001). However, the frequency of short/short genotype observed in the GAD patients was higher than that in healthy subjects (68% versus 49%, w 2 = 12.274, df = 2, P = 0.002), and the frequency of short allele in GAD patients was higher than that in controls (79 versus 71%, w 2 = 4.063, df = 1, P = 0.044).…”

Association Study and Meta-Analysis of Polymorphisms, Methylation Profiles, and Peripheral mRNA Expression of the Serotonin Transporter Gene in Patients with Alzheimer's Disease

“…The 12 excluded papers included 6 studies that did not examine healthy controls, and 6 reviews and brief reports. Five case-control datasets were included in the meta-analysis of the Asian population, which included 524 cases and 699 controls [24,26,52,53]. Ten case-control datasets were included in the meta-analysis of the Caucasian population, which included 1,436 cases and 1,342 controls.…”