alexa The Gene Polymorphism of VMAT2 Decrease the Risk of Developing SCZ in Male Han Chinese

Journal of Genetics and DNA Research

Reach Us +44-1235-425476
  • Review   
  • J Genet DNA Res 2017, Vol 1(1): 104

The Gene Polymorphism of VMAT2 Decrease the Risk of Developing SCZ in Male Han Chinese

Hongying Han1, Xinglong Yang2, Zeng Zhang3, Chuanxin Liu3,4, Jinxiang Zhang3, Xiuyan Wang5 and Yanming Xu2*
1Department of Psychiatry, The Third Affiliated Hospital of Sun Yat-sen University, 600 Tianhe RD, Guangzhou, Guangdong, PR China
2Department of Neurology, West China Hospital, Sichuan University, 37 Guo Xue Xiang, Chengdu, Sichuan Province, PR China
3Department of Psychiatry, Jining Mental Hospital, Jining, Shandong Province, PR China
4College of Basic and Forensic Medicine, Sichuan University, Chengdu, Sichuan Province, PR China
5Institute of Mental Health, The Second Xiangya Hospital, Central South University, Changsha, Hunan Province, PR China
*Corresponding Author: Yanming Xu, Department of Neurology, West China Hospital, Sichuan University, 37 Guo Xue Xiang, Chengdu, Sichuan Province, 610041, PR China, Tel: +86 2885422891, Email: [email protected]

Received Date: Oct 09, 2017 / Accepted Date: Oct 12, 2017 / Published Date: Oct 17, 2017

Abstract

Introduction

Schizophrenia (SCZ) is the most common Psychiatric disorders incidence of 1% worldwide and of which the pathophysiology was still elusive. SCZ is a complicate disease which many gene and environmental factors were involved in the pathogenic of it [1]. Among numerous physiologic mechanism of SCZ, DA hypothesis was the most accepted one which means excessive activity or drugs which increase dopamine activity may induce psychiatric symptom. And in the clinic practice, the dopaminergic receptor agonist (eg: chlorpromazine, clozapine, risperidone) were extensively used to treat SCZ.

Many GWAS study and associate studies have detected may gene factors associated with SCZ, which indicate a genetic background of patients with SCZ [2-4]. VMAT2 gene was located at 10q25, which is a suspected locus of schizophrenia (SCZ) detected by a systematic genome wide linkage study with a LOD score of 3.87 [5]. VMAT2 protein is mainly expressed in the brain and play an important role in the transmission of monoamine including DA.

Recently, an Italy research reported that two SNP (rs363371, rs36334) in the promoter region of VMAT2 were detected associated PD. Since DA hypothesis was the common base of both SCZ and PD.

For patient with PD, deficiency of DA in substantia nigra account for the main clinic characters of Parkinsonism. Nevertheless, the new revised DA hypothesis of SCZ is hyperactive dopamine transmission in the mesolimbic areas and hypoactive dopamine transmission in the prefrontal cortex in schizophrenia patients [6]. And interestingly, both SCZ and PD have shared some common gene risk factors such as MMP9 [7,8], MAOB, COMT [9-11]. Thus as the shared pathogenic mechanism and genetic factors of SCZ and PD, we conduct a casecontrol study to detect the association between VMAT2 gene polymorphism and SCZ in Han Chinese population.

Material and Method

Subject

A total of 430 (male 185; female 245; mean age 41.27 ± 14.40, mean onset age 25.05 ± 8.69 yr) patients with SCZ were recruited from three psychiatric disorder center: The Second Xiangya Hospital of Central South University, located in central China; West China Hospital of Sichuan University, located in southwest China; and the Third Affiliated Hospital of Sun Yat-sen University and Jining Mental Hospital, both located in east China. All patients were diagnosed by two psychiatrists based on the Structured Clinical Interview for DSM Disorders (SCID) and DSM-IV criteria [12]. Patients who were older than 18 at SCZ onset were subdivided into late-onset SCZ (LOSCZ; n=290 mean age at onset, 27.71 ± 7.96 yr); the others were as earlyonset SCZ group (EOSCZ; n=140; mean age at onset, 15.57 ± 2.05 yr) [13]. The control group for SCZ patients comprised 457 Han Chinese (190 males, 280females; mean age, 42.33 ± 12.45 yr). The protocol of the study was approved by the ethics committees of all three hospitals involved in this research, all the written inform consents were got from all the subjects involved in this study (Table 1).

Characteristic SCZ (n=430) Controls (n=470) Comparison*
Age inyr, mean ± SD 41.27±14.40 42.33±12.45 t=, p=
Gender, n  
Male 185 190 0.80, 0.63-1.02, 3.14, 0.08
Female 245 280
*Unless otherwise indicated, the values indicate: OR, 95%CI, c2, p value.

Table 1: Demographic characteristics of Han Chinese with schizophrenia (SCZ) and healthy controls.

Genotyping

Genomic DNA was obtained from peripheral leukocytes by the classic Phenol-chloroform DNA extract method. All the genotyping experiments were done by the Shanghai Bio-Wing Applied Biotechnology Company using ligase detection reactions (LDR) [14]. The target DNA sequences were amplified using a multiplex PCR method. The primary information for rs363371 and rs363324 (Table S1).

After the completion of the amplification, 1 μl of Proteinase K (20 mg/ml) was added, then heated at 70°C for 10 min and quenched at 94°C for 15 min. The ligation reaction for each subject was carried out in a final volume of 20 μl containing 20 mM Tris-HCl (pH 7.6),25 mM potassium acetate, 10 mM magnesium acetate, 10 mM DTT, 1 mM NAD, 0.1% Triton X-100, 10 μl of MultiPCR product, 1 pmol of each discriminating oligo, 1 pmol of each common probe and 0.5 μl of 40 U/ μl Taq DNA ligase (New England Bio labs, USA). The LDR was performed using 40 cycles of 94°C for 30 sec and 63°C for 4 min. The fluorescent products of LDR were differentiated by ABI sequencer 377.

Statistical analysis

Values for age were represented by the mean ± standard deviation (SD), and the gender, allele and genotype were described as percentages. Allele and genotype frequencies were determined by direct counting of HNMT alleles. Concordance of genotype distribution was verified by Hardy-Weinberg Equilibrium (HWE) and then evaluated with the chi-square test. Associations between gender, allele and genotype were also assessed by chi-square test. Age differences between three groups were assessed by the t test. A twotailed P value<0.05 was considered significant. Statistical SPSS17.0 was used when conduct both chi-square test and t test. Haplotype analysis was conducted by SHEsis 4.0 online (http://analysis.bio-x.cn/ myAnalysis.php).

Result

From our data, for the SNP rs363371 there were no obvious significant differences of the distribution between the SCZ group and control group (OR=1.607, 95%CI 0.761-1.495, p=0.709) or between the subgroups in dominant model (Table 2). While in the recessive model, there was an obvious significant difference between the male SCZ group and the male controls (OR, 0.564, 95%CI 0.357-0.892, p=0.014). There was not any statistic significant between the SCZ group and the control group, the SCZ female group and controls, the EOSCZ, LOSCZ and control group (Table 2).

  Group or subgroup Genotype, n (%)  Comparisonb
GG AG AA Dominant model Recessive model
Locus rs363371  
All SCZ 81 (18.8) 227 (52.8) 122 (28.4) 1.607, 0.761-1.495, 0.14, 0.709c 0.915, 0.686-1.22, 0.367, 0.545c
Male SCZ 32 (17.3) 111 (60) 42 (22.7) 1.013, 0.591-1.736, 0.002, 0.962 0.564, 0.357-0.892, 6.059, 0.014d
Male controls 32 (17.1) 91 (48.7) 64 (34.2)  
Female SCZ 49 (20) 116 (47.3) 80 (32.7) 1.239, 0.796-1.930, 0.903, 0.342 1.112,0.769-1.609, 0.32,0.572d
Female controls 47 (16.8) 148 (52.8) 85 (30.4)  
EOSCZ 26 (18.7) 80 (57.6) 33 (23.7) 1.057, 0.65-1.721, 0.05, 0.823 0.719, 0.464-1.114, 2.194, 0.139
LOSCZ 55 (18.9) 147 (50.5) 89 (30.6) 1.071, 0.735-1.561, 0.127, 0.721 1.018, 0.741-1.398, 0.012, 0.914
All controls 84 (17.9) 244 (51.9) 142(30.2)  
Locus rs363324  
SCZ 265 (61.6) 147 (34.2) 18 (4.2) 0.968, 0.739-1.268, 0.056, 0.813c 1.088, 0.553, 2.138, 0.06, 0.807c
Male SCZ 111 (62) 63 (35.2) 5 (2.8) 0.941, 0.615-1.438, 0.08, 0.829 0.735, 0.229-2.359, 0.27, 0.603d
Male controls 118 (63.4) 61(32.8) 7 (3.8)  
Female SCZ 154 (61.4) 84 (33.5) 13 (5.2) 0.985, 0.695-1.398, 0.007, 0.934 1.486,0.64-3.45,0.858,0.354d
Female controls 174 (61.7) 98 (34.8) 10 (3.5)  
EOSCZ 84 (60) 49 (35) 7 (5) 0.904, 0.614-1.331, 0.262, 0.609 1.396, 0.567-3.438, 0.532, 0.466c
LOSCZ 181 (62.4) 98 (33.8) 11 (3.8) 1.001, 0.704-1.354, 000, 0.995 1.046, 0.483-2.266, 0.013, 0.909c
All controls 292 (64.4) 159 (34) 17 (3.6)  
Abbreviations: SCZ, schizophrenia; EOSCZ, early-onset SCZ; LOSCZ, late-onset SCZ
aFrequencies of individual alleles (not shown) did not differ significantly between the entire SCZ group or subgroup and healthy controls.
bValues indicate: OR, 95%CI, c2, p value
cWith respect to all controls
dWith respect to the corresponding male or female controls

Table 2: Genotype frequencies between the entire group or subgroups of Han Chinese with SCZ and healthy controls a.

For the other SNP rs363324, there were not obvious differences between the SCZ group and control group and between the subgroups in both dominant and recessive model (Table 2). For the two SNPs the allele frequencies were not different in any compared groups (Table S2).

The linkage disequilibrium D’ value between rs363371 and rs363324 was 0.334 for rs373371 and rs363324, suggesting a strong recombination event. Thus we conduct a Haplotype analysis, in which haplotypes with frequencies<0.03 were excluded, identified the three haplotypes A-G, G-A, and G-G. None of these haplotypes showed a significant association with SCZ (Table 3).

SNP Haplotype* SCZ, n (%) Control, n (%) c2 p OR [95% CI]
1,2 A-G 470 (54.8) 522 (56.1) 0.323 0.57 0.947 [0.786-1.142]
  G-A 183 (21.3) 195 (20.9) 0.044 0.834 1.025 [0.816-1.286]
  G-G 205 (23.9) 214 (23.0) 0.216 0.642 1.053 [0.846-1.311]
*Only haplotypes with a frequency of p>0.03 were considered in the analysis. A,G, indicates the allele of rs363371; A,G indicates the allele of rs363324

Table 3: Haplotype frequencies at loci rs363371 and rs363324 in Han Chinese with SCZ and healthy controls.

Discussion

Our data did not detect an association between the two SNPs in VMAT2 gene and PD. Our study was consistence with a previously study which failed to detected an association between VMAT 2 and SCZ, nonetheless that study did not including the two SNPs of our study [15]. Interesting,we detect the AA genotype of rs363371 as protecting male Han Chinese from developing SCZ (OR,0.564,95%CI 0.357 to 0.892,p=0.014). And this locus, located in the promoter of VMAT2 , is potential functional. As it in linkage disequilibrium with locus rs2619096, which doubles the activity of the VMAT2 promoter [16].

Although many research show a relationship between VMAT2 pathophysiology of neuropsychiatric diseases including schizophrenia, mood disorders, methamphetamine (MAP) neurotoxicity [17-19]. In patients with SCZ, it was reported that the density of VMAT2 protein increased in an investigation of platelets, which may indicate a schizophrenia-related hyperactivity of the monoaminergic system or an adaptive response to chronic drug treatment [20]. In a 14-3-3 epsilon hetero KO mice model of schizophrenia expression of VMAT2 was increased significantly in the hippocampal, indicate a possible pathophysiology of schizophrenia includes a monoaminergic transmission abnormality [21]. Recently, a research showed that genetic variation in VMAT2 may be linked to alterations in cognitive functioning underlying psychotic disorder [22].

Interestingly, our study show a significant difference of AA genotype of rs363371 between the male SCZ group and male controls, while there was not detect such a similar difference between the female SCZ group and female controls. It seems contrary to a GWAS research which supports the idea that no strong sex-specific genetic risk factors exist for schizophrenia [23]. But indeed, there were some support evidence. A case-control study show a gender difference of gene factors, the study show interleukin 1 receptor antagonist protein (IL1Ra) and IGF2BP2 was associated with SCZ in male population but not in female [24,25]. C allele and CC genotype of rs253 was reported confer risk for schizophrenia in men [26]. A male-specific association was also be reported with SNP rs62621676 in a UK case-control cohort [27]. While, there were more female-specific genetic factor. Two casecontrol study from China show that high-affinity neurotensin receptor 1(NTR1) gene polymorphism and estrogen receptor 1(ESR1 ) gene polymorphism were increase the risk of developing SCZ in female Chinese population [28,29]. A GWAS research found an female- specific association with rs7341475 in reelin (RELN ) gene [30]. Most interestingly, in a study show in a same gene, different SNPs conduct different sex-spefic effect: eg,SNPs rs3891636, rs7728773, rs2189663,rs3864283, and rs2526303 of HINT1 gene significant among the female subjects alone, whereas SNP rs7735116 was significant among males alone [31]. These studies indicate there may exit sexspecific genetic risk and protective factors to SCZ.

In terms of us understand, it is the first case-control study try to detect a potential relationship between SCZ and the two potential functional SNPs of VMAT2 in Chinese population. Nevertheless, Our result have some limitations: Firstly, the relative small sample size may alleviate the power our research(the power for rs363371 was 80.8% while for rs363324 was only 5.1%); Secondly, we only select two SNP in the promoter region and for this low coverage of SNPs the really risky SNP may be neglected; Thirdly, we did not take other risk factors associated SCZ (eg: environmental and social factors) into consideration; Moreover, as a recently research indicated VMAT2 was associated with Tardive dyskinesia(TD), an involuntary movement disorder that can occur in up to 25% of patients receiving long-term first-generation antipsychotic treatment [32]. Thus, the gene-medical treatment should be take into consideration in the future study.

In conclusion, our research indicate the rs363371, rs363324 were not associated with SCZ, while it was seems that the AA genotype of rs363371 conduct a protect effect in male Chinese in developing into SCZ. In the future study more SNPs should be included and more risk factor should be involved in much bigger sample size and different ethnic.

Acknowledgments

This research was supported by the Sichuan Key Project of Science and Technology (no. 2010SZ0086).

References

Citation: Han H, Yang X, Zhang Z, Liu C, Zhang J, et al. (2017) The Gene Polymorphism of VMAT2 Decrease the Risk of Developing SCZ in Male Han Chinese. J Genet DNA Res 1:104.

Copyright: © 2017 Han H, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Select your language of interest to view the total content in your interested language

Post Your Comment Citation
Share This Article
Relevant Topics
Recommended Conferences
Article Usage
  • Total views: 435
  • [From(publication date): 0-2017 - Jan 19, 2019]
  • Breakdown by view type
  • HTML page views: 406
  • PDF downloads: 29

Post your comment

captcha   Reload  Can't read the image? click here to refresh
Leave Your Message 24x7