Printer Friendly

Case control study of association between the ANK3 rs10761482 polymorphism and schizophrenia in persons of Uyghur nationality living in Xinjiang China.

1. Background

Although linkage studies suggested that genetic factors play a major role in the onset and course of schizophrenia, the exact mechanisms remain unclear. [1] One gene of particular interest is ANK3, located on chromosome 10q21. It acts on the early development of the Ranviers nodes of axons in the central and peripheral nervous systems [2] and, thus, plays a key role in the regulation and differentiation of the nervous system. [3] When the ANK3 gene is knocked out in mice, the mice show abnormal hypothalamic--pituitary--adrenal axis (HPA) functioning. [4] Ankyrin G (ANKG), which is encoded by the ANK3 gene, is crucial for the stability of the neuronal membrane [5, 6] and facilitates the connection between axons and ribbon synapses. [7] ANKG also regulates ion channels involved in the release of neurotransmitters; [8] abnormal expression of ANKG may induce abnormal activity in glutamate receptors (GluRs). [9] Many studies have demonstrated that abnormal release of brain neurotransmitters in different neural pathways is involved in the pathogenesis of schizophrenia. Thus, HPA axis dysfunction and abnormal glutamate activity--both of which are influenced by ANK3--are key targets in the search for the genetic causes of schizophrenia.

Several studies suggest that ANK3 is important in the pathogenesis of schizophrenia. Athanasiu and colleagues conducted a genome-wide association study (GWAS) in 2663 European individuals with schizophrenia and 13,780 controls and reported that the ANK3 gene rs10761482 polymorphism was associated with schizophrenia. [10] Yuan and colleagues found the same results in a sample of Han Chinese. [11] Another study reported that the ANK3 was also related to the age of onset of schizophrenia. [12] In this study, we aim to assess the relationship of the ANK3 rs10761482 polymorphism with schizophrenia among individuals of Uyghur decent (one of China's large ethnic minority groups) living in the Xinjiang region of western China and determine whether or not the polymorphism is different in persons with schizophrenia who have an early versus late age of onset.

2. Methods

2.1 Sample

Figure 1 shows the enrollment process for the study. All the participants were natives to Xinjiang of the Uyghur nationality and had no biological connections with each other. Two senior psychiatrists conducted the diagnosis and collected the clinical data in the patient group. We provided a detailed explanation to all participants about the purpose of this study and obtained informed consent signed by the subjects or their guardians. This study was approved by the Ethics Committee of the First Affiliated Hospital of Xinjiang Medical University.

2.1.1 Case group

A total of 649 Uyghur inpatients diagnosed with schizophrenia were recruited from six hospitals in the Xinjiang Uyghur Autonomous Region of China between January 2011 and May 2013: the Department of Psychology of the First Affiliated Hospital of Xinjiang Medical University, the Urumqi Peace Hospital, the Hotan Mental Health Hospital, the Kashgar First People's Hospital, the Yili Mental Health Hospital, and the Aksu Prefecture Kangning Hospital. Inclusion criteria were: (a) 20 to 80 years of age; (b) diagnosis of schizophrenia based on the criteria specified in the Diagnostic and Statistical Manual of Mental Disorders 4th edition (DSMIV) as assessed by two trained psychiatrists using the Chinese version of the Structured Clinical Interview for DSM-IV (SCID) [13]; (c) no mental retardation or other mental disorders; (d) no family history of mental illnesses; (e) no central nervous system diseases or traumatic brain injury; and (f) no serious physical illnesses, such as cancer, endocrine disease, severe cardiovascular disease, or liver or kidney dysfunction.

The 649 patients in the case group included 389 (60%) males and 260 (40%) females. Their mean (sd) age was 44.4 (12.1) years. Among them, 134 (75 males and 59 females) had the first onset of illness when they were 18 years of age or younger (the 'adolescent-onset' group); the remaining 515 (314 males and 201 females) had the first onset after 18 years of age (the 'adult-onset' group).

2.1.2 Control group

Individuals of the Uyghur minority who participated in a routine physical examination at the First Affiliated Hospital of Xinjiang Medical University from May 2012 to May 2014 were potential control subjects. They had to meet the same inclusion criteria as the case group (above) except that they had no present or prior history of mental disorders. Potential participants were administered the Composite International Diagnostic Interview (CIDI) by psychology research fellows to identify those with current or past mental illnesses. A total of 557 control subjects participated in the study, including 303 (54%) males and 254 (46%) females. Their mean age was 45.1 (15.50) years.

There was a borderline excess of males in the case group compared to the control group (60% vs. 54%; [chi square] = 3.76, p = 0.052) but there was no significant difference in the mean age of the two groups (t = 0.82, p = 0.414).

2.2 Genotype assessment

Two milliliters of venous blood was drawn from each participant. Blood samples were prepared for genotyping using the DNA extraction system provided by the Tiangen Biotech Company in Beijing.

Based on findings from previous GWAS studies, we selected the loci rs10761482 of the ANK3 gene for genotyping. According to the PubMed nucleic acid database, the rs10761482 (C/T) is in the first intron of the ANK3 gene in Asian and European populations and the allele frequencies were greater than 0.1.

Taqman probe-based polymerase chain reaction (PCR) was used for genotyping. PCR was conducted using the GeneAmp PCR 9700 system (Applied Biosystem). Each well of the 384-well plate contains 5pl of PCR reaction material: 40ng DNA, 2.5[micro]l PCR reaction mixture, and 0.035[micro]l Taqman probes. Forty five cycles of amplification were performed using the following settings: 95[degrees]C for 10 minutes, 92[degrees]C for 15 seconds, and 60[degrees]C for 1 min. The product was genotyped using the ABI 7900 DNA detection system (Applied Biosystem, Foster City, CA, USA). In the patient group 97.1% (630/649) of the samples were successfully genotyped; in the control group 96.1% (535/557) were successfully genotyped. In order to ensure accuracy and reliability, we randomly selected 3% of the samples from each of the two groups to genotype again; the same results were obtained from all of these re-tested samples.

2.3 Statistical Analysis

Microsoft Excel was used to construct the database. SPSS17.0 software was used for analysis. Two-sample t-test was used to compare the age of onset and [chi square] test was used to compare the male-female ratios. In addition, the SHEsis software (http://analysis.bio-x.cn) was used to test if the data were in accordance with the Hardy-Weinberg equilibrium (HWE) and to analyze differences in the allele frequencies and genotypes between the two groups. Due to the borderline difference in the male-female ratios between the two groups, we also conducted a stratified analysis by gender.

3. Results

3.1 Comparisons of the allele and genotype frequencies between the case group and control group

The distribution of the rs10761482 polymorphisms met the Hardy-Weinberg equilibrium (HWE) requirements in all four subgroups of subjects considered in this analysis: male cases (p = 0.059), male controls (p = 0.116), female cases (p = 0.956), and female controls (p = 0.855). No statistically significant differences were found in the rs10761482 allele and genotype frequencies between the 630 cases and 535 controls who were successfully genotyped. As shown in Table 1, similar results were found when the analysis was stratified by gender; neither the allele frequency nor the genotype frequency were significantly different between male cases and controls or between female cases and controls.

Separate comparison of the results of the 381 males with schizophrenia who were successfully genotyped and the 249 females with schizophrenia who were successfully genotyped found no significant difference by gender in the allele frequency (OR = 1.01, Cl = 0.77~1.33, p = 0.942) or in the genotype frequency ([chi square] = 1.52, p = 0.468).

3.2 Association between the onset age and the ANK3 gene rs10761482 polymorphism

As shown in Table 2, there were no differences in either the genotype or the allele frequencies of the ANK3 rs10761482 polymorphism between the 131 individuals with adolescent-onset schizophrenia and the 499 individuals with adult-onset schizophrenia who successfully completed the genotyping. Stratified analysis revealed similar results by gender: the frequencies of alleles and genotypes between male adolescent-onset and adult-onset patients with schizophrenia were not significantly different, and the frequencies of alleles and genotypes between female adolescent-onset and adult-onset patients were also not significantly different.

Separate analyses comparing the 131 adolescent-onset patients' results to those of all 535 controls found no difference in allele frequency (OR = 0.97, Cl = 0.59~1.45, p = 0.871) or in genotype frequency ([chi square] = 0.06, p = 0.971). A similar comparison of the 499 adult-onset patients' results to those of all controls found no difference in allele frequency (OR = 1.01, Cl = 0.82~1.28, p = 0.907) or in genotype frequency ([chi square] = 0.02, p = 0.992). These comparisons remained statistically insignificant after stratifying by gender (results provided on request).

4. Discussion

4.1 Main findings

This study is the first to explore the role of the ANK3 gene in schizophrenia in a relatively large sample of individuals of Uyghur descent. We found no statistically significant differences between cases and controls in either the allele frequencies or the genotypes of one of the ANK3 polymorphisms that is most frequently associated with schizophrenia. We also found no link between the ANK3 rs10761482 polymorphism and the age of onset of schizophrenia. Other studies [14] have also failed to replicate findings about the role of ANK3 in schizophrenia, but the weight of the evidence--including a meta-analysis [11] confirming the role of allele C of the ANK3 rs10761482 polymorphism and of allele T of the rs10994336 locus--still supports the hypothesized role of ANK3 in the pathogenesis of schizophrenia. Several studies have identified mechanisms via which ANK3 could be involved; for example, allele C of the ANK3 rs9804190 polymorphism is associated with the down-regulation of mRNA expression in schizophrenia. [15] Nevertheless, our negative findings and those of other investigators suggest that other factors may play a role in moderating the effects of ANK3.

4.2 Limitations

Several factors may have contributed to our null findings. (a) The study sample was limited to individuals of the Uyghur minority group in China, a fairly homogenous group (with limited out-group marriage) that has both European and Asian genetic characteristics. Despite the similar C allele frequency of the locus rs10761482 in our sample (78%) to that reported for the European and Asian populations (74.8% and 75%, respectively, based on the PubMed database), the Uyghur group may have unique genetic characteristics that alter the relationship between ANK3 and schizophrenia. (b) In limiting our sample to individuals with schizophrenia who do not have a family history of mental illness, we may have decreased the relative importance of genetic factors in the group of patients considered in the analysis. (c) We did not assess several other ANK3 loci that may be related to the pathogenesis of schizophrenia including rs10761482, rs9804190, and rs10994336. [11, 15] (d) Some studies suggest that genetic polymorphisms are associated with specific clinical subtypes of schizophrenia; [16, 17] other than considering age of onset, we did not subclassify our results by other potentially important factors. (e) The sample size was too small to justify stratifying results by multiple variables.

4.3 Implications

Replication of widely accepted genetic findings about psychiatric illnesses in different, relatively homogenous ethnic groups may help identify factors that moderate the role of these presumed 'universal' genetic factors. Our failure to replicate findings of a relationship between the ANK3 gene rs10761482 polymorphism and schizophrenia in a relatively large sample of patients with schizophrenia from the Uyghur minority group in western China is an example of the potential promise of such studies. If these results are replicated in further studies, then the focus should change to understanding why this widely acknowledged association does not exist in this particular ethnic group. Such follow-up studies would have considerable value in highlighting the genetic environment in which ANK3 does or does not exert a role in the pathogenesis of schizophrenia.

Acknowledgements

The authors thank all the investigators for their assistance in this project, and the Bio-X Institute of Shanghai Jiao Tong University for providing technical support.

Conflict of Interest

The authors report no conflicts of interests related to this study.

Funding

This work was supported by the Natural Science Foundation of China (project name: 'de novo CNV in schizophrenia in persons of Uyghur nationality in Xinjiang', no. 81360209) and the Xinjiang Uyghur Autonomous Region Science and Technology Fund (project name: 'Establishing a genetic database for depression in persons of Uyghur nationality in Xinjiang', no. 2010211A51).

Ethical approval

This study was approved by the Ethics Committee of the First Affiliated Hospital of Xinjiang Medical University.

Informed consent

All participants or their guardians provided written informed consent to participate in the study.

References

[1.] Farmer AE, McGuffin P. The pathogenesis and management of schizophrenia. Drugs. 1988; 35: 177-185

[2.] Kapfhamer D, Miller DE, Lambert S, Bennett V, Glover TW, Burmeister M. Chromosomal localization of the ankyrinG gene (ANK3/Ank3) to human 10q21 and mouse 10. Genomics. 1995; 27(1): 189-191. doi: http://dx.doi. org/10.1006/geno.1995.1023

[3.] Hansell NK, Medland SE, Ferreira MAR, Geffen GM, Zhu G, Montgomery GW, et al. Linkage analyses of event-related potential slow wave phenotypes recorded in a working memory task. Behav Genet. 2006; 36(1): 29-44. doi: http:// dx.doi.org/10.1007/s10519-005-9002-2

[4.] Sobotzik JM, Sie JM, Politi C, Del Turco D, Bennett V, Deller T, et al. AnkyrinG is required to maintain axo-dendritic polarity in vivo. Proc Natl Acad Sci USA. 2009; 104(41): 17564-17569. doi: http://dx.doi.org/10.1073/pnas.0909267106

[5.] Bennett V. Ankyrins: adaptors between diverse plasma membrane proteins and the cytoplasm. J Biol Chem. 1992; 267(13): 8703-8706

[6.] Bennett V, Otto E, Kunimoto M, Kordeli E, Lambert S. Diversity of ankyrins in the brain. Biochem Soc Trans. 1991; 19(4): 1034-1039

[7.] Hedstrom KL, Ogawa Y, Rasband MN. AnkyrinG is required for maintenance of the axon initial segment and neuronal polarity. Cell Biol. 2008; 183(4): 635-640. doi: http://dx.doi. org/10.1083/jcb.200806112

[8.] Kosaka T, Komada M, Kosaka K. Sodium channel cluster, betaIV-spectrin and ankyrinG positive "hot spots" on dendritic segments of parvalbumin-containing neurons and some other neurons in the mouse and rat main olfactory bulbs. Neurosci Res. 2008; 62(3): 176-186. doi: http://dx.doi. org/10.1016/j.neures.2008.08.002

[9.] Talkowski ME, Rosenfeld JA, Blumenthal I, Pillalamarri V, Chiang C, Heilbut A, et al. Sequencing chromosomal abnormalities reveals neurodevelopmental loci that confer risk across diagnostic boundaries. Cell. 2012; 149(3): 525-537. doi: http://dx.doi.org/10.1016/j.cell.2012.03.028

[10.] Athanasiu, L, Mattingsdal M, Kahler AK, Brown A, Gustafsson O, Agartz I, et al. Gene variants associated with schizophrenia in a Norwegian genome-wide study are replicated in a large European cohort. J Psychiatr Res. 2012; 44(12): 748-753. doi: http://dx.doi.org/10.1016/jjpsychires.2010.02.002

[11.] Yuan A, Yi Z, Wang Q, Sun J, Li Z, Du Y, et al. ANK3 as a risk gene for schizophrenia: new data in Han Chinese and meta analysis. Am J Med Genet B Neuropsychiatr Genet. 2012; 159(8): 997-1005. doi: http://dx.doi.org/10.1002/ajmg. b.32112

[12.] Talkowski ME, Rosenfeld JA, Blumenthal I, Pillalamarri V, Chiang C, Heilbut A, et al. Sequencing choromosomal abnormalities reveals neurodevelopmental loci that confer risk across diagnostic boundaries. Cell. 2012; 149(3): 525-537. Epub 2012 Apr 19. doi: http://dx.doi.org/10.1016/ j.cell.2012.03.028

[13.] Phillips MR, Liu XH. Adapted Chinese version of Structured Clinical Interview for DSM-IV-TR Axis I Disorders, Research Version, Patient Edition (SCID-I/P) by Michael B. First, Robert L. Spitzer, Miriam Gibbon, and Janet B.W. Williams. Shanghai: Suicide Research and Prevention Center, Shanghai Mental Health Center; 2011

[14.] Gella A, Segura M, Durany N, Pfuhlmann B, Stober G, Gawlik M. Is Ankyrin a genetic risk factor for psychiatric phenotypes? BMC Psychiatry. 2011; 11(103): 1-5. doi: http://dx.doi.org/10.1186/1471-244X-11-103

[15.] Roussos P, Katsel P, Davis KL, Bitsios P, Giakoumaki SG, Jogia J, et al. Molecular and genetic evidence for abnormalities in the nodes of Ranvier in schizophrenia. Arch Gen Psychiatry. 2012; 69(1): 7-15. doi: http://dx.doi.org/10.1001/ archgenpsychiatry.2011.110

[16.] Su L, Wei B, Chen Q, Feng Q, Pan R, Zhou Y, et al. [Association study of PRODH gene variant rs385440 with schizophrenia in Zhuang and Han nationality of Guangxi]. Zhonghua Xing Wei Yi Xue Yu Nao Ke Xue Za Zhi. 2012; 21(1): 36-39. Chinese

[17.] Guo W, Li W, Zhang H, Hao W. [Association study of disrupted-in-schizophrenia-1 gene single nucleotide polymorphism with schizophrenia in Han Chinese population]. Zhonghua Xing Wei Yi Xue Yu Nao Ke Xue Za Zhi. 2012; 21(4): 337-339. Chinese

(received: 2014-03-20; accepted: 2014-07-01)

Xianjiang Zhong obtained his Master's degree from Xinjiang Medical University in June 2014. He has been a resident physician in the Mental Health Department of the First People's Hospital in Xiantao City, Hubei Province since July 2014. His research interest is in the molecular genetics of schizophrenia.

Xianjiang ZHONG (1, 2), Lili ZHANG (1, 3), Shuxian HAN (1), Xiao LUO (1), Zhiguo AN (1), Qizhong YI (1) *

(1) First Affiliated Hospital of Xinjiang Medical University, Xinjiang Uyghur Autonomous Region, China

(2) First People's Hospital of Xiantao City, Hubei Province, China

(3) Sixth People's Hospital of Hebei Province, Hebei Province, China

* correspondence: qizhongyi@126.com

Table 1. Comparisons of allele and genotype frequencies of the
ANK3 gene rs10761482 polymorphism between persons of Uyghur
nationality with and without schizophrenia

rs10761482                            Allele

                    C            T        odds       95%CI        p
                  n (%)        n (%)      ratio

BOTH GENDERS
cases (n=630)   983 (78.0)   277 (22.0)   1.00    [0.83~1.22]   0.967
controls        834 (77.9)   236 (22.1)
  (n=535)
MALES
cases (n=381)   595 (78.1)   167 (21.9)   0.98    [0.75~1.27]   0.855
controls        460 (78.5)   126 (21.5)
  (n=293)
FEMALES
cases (n=249)   388 (77.9)   110 (22.1)   1.04    [0.77~1.40]   0.810
controls        374 (77.3)   110 (22.7)
  (n=242)

rs10761482                            Genotype

                   C/C          C/T         T/T       [chi       p
                  n (%)        n (%)       n (%)     square]

BOTH GENDERS
cases (n=630)   377 (59.8)   229 (36.3)   24 (3.8)    0.01     0.995
controls        320 (59.8)   194 (36.3)   21 (3.9)
  (n=535)
MALES
cases (n=381)   226 (59.3)   143 (37.5)   12 (3.1)    0.04     0.981
controls        176 (60.1)   108 (36.9)   9 (3.1)
  (n=293)
FEMALES
cases (n=249)   151 (60.6)   86 (34.5)    12 (4.8)    0.07     0.967
controls        144 (59.5)   86 (35.5)    12 (5.0)
  (n=242)

CI, confidence interval

Table 2. Comparisons of allele and genotype frequencies of the
ANK3 gene rs10761482 polymorphism between persons of Uyghur
nationality with adolescent-onset schizophrenia (ADL) and persons
of Uyghur nationality with adult-onset schizophrenia (ADU)

rs10761482                            Allele

                   C            T        odds       95%CI        p
                 n (%)        n (%)      ratio

BOTH GENDERS
ADL group      203 (77.5)   59 (22.5)    0.96    [0.69~1.33]   0.814
  (n=131)
ADU group      780 (78.2)   218 (21.8)
  (n=499)
MALES
ADL group      113 (76.4)   35 (23.6)    0.88    [0.80~1.35]   0.570
  (n=74)
ADU group      482 (78.5)   132 (21.5)
  (n=307)
FEMALES
ADL group      90 (78.9)    24 (21.1)    1.08    [0.65~1.80]   0.761
  (n=57)
ADU group      298 (77.6)   86 (22.4)
  (n=192)

rs10761482                           Genotype

                  C/C          C/T         T/T       [chi       p
                 n (%)        n (%)       n (%)     square]

BOTH GENDERS
ADL group      77 (58.8)    49 (37.4)    5 (3.8)     0.08     0.960
  (n=131)
ADU group      300 (60.1)   180 (36.1)   19 (3.8)
  (n=499)
MALES
ADL group      43 (58.1)    27 (36.5)    4 (5.4)     1.53     0.465
  (n=74)
ADU group      183 (59.6)   116 (37.8)   8 (2.6)
  (n=307)
FEMALES
ADL group      34 (59.6)    22 (38.6)    1 (1.8)     1.81     0.405
  (n=57)
ADU group      117 (60.9)   64 (33.3)    11 (5.7)
  (n=192)

CI, confidence interval
COPYRIGHT 2014 Shanghai Mental Health Center
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 2014 Gale, Cengage Learning. All rights reserved.

Article Details
Printer friendly Cite/link Email Feedback
Title Annotation:Original article
Author:Zhong, Xianjiang; Zhang, Lili; Han, Shuxian; Luo, Xiao; An, Zhiguo; Yi, Qizhong
Publication:Shanghai Archives of Psychiatry
Article Type:Report
Date:Oct 1, 2014
Words:3428
Previous Article:Cross-sectional study of the association of cognitive function and hippocampal volume among healthy elderly adults.
Next Article:Should major depressive disorder with mixed features be classified as a bipolar disorder?
Topics:

Terms of use | Privacy policy | Copyright © 2018 Farlex, Inc. | Feedback | For webmasters