Genetic association between NRG1 and schizophrenia, major depressive disorder, bipolar disorder in Han Chinese population.

Schizophrenia, major depressive disorder, and bipolar disorder are three major psychiatric disorders affecting around 0.66%, 3.3%, and 1.5% of the Han Chinese population respectively. Several genetic linkage analyses and genome wide association studies identified NRG1 as a susceptibility gene of schizophrenia, which was validated by its role in neurodevelopment, glutamate, and other neurotransmitter receptor expression regulation. To further investigate whether NRG1 is a shared risk gene for major depressive disorder, bipolar disorder as well as schizophrenia, we performed an association study among 1,248 schizophrenia cases, 1,056 major depression cases, 1,344 bipolar disorder cases, and 1,248 controls. Totally 15 tag SNPs were genotyped and analyzed, and no population stratification was found in our sample set. Among the sites, rs4236710 (corrected Pgenotye = 0.015) and rs4512342 (Pallele = 0.03, Pgenotye = 0.045 after correction) were associated with schizophrenia, and rs2919375 (corrected Pgenotye = 0.004) was associated with major depressive disorder. The haplotype rs4512342-rs6982890 showed association with schizophrenia (P = 0.03 for haplotype "TC" after correction), and haplotype rs4531002-rs11989919 proved to be a shared risk factor for both major depressive disorder ("CC": corrected P = 0.009) and bipolar disorder ("CT": corrected P = 0.003). Our results confirmed that NRG1 was a shared common susceptibility gene for major mental disorders in Han Chinese population.

Common variants in QPCT gene confer risk of schizophrenia in the Han Chinese population.

Schizophrenia (SCZ) is a common and severe mental disorder, its etiology has not been elucidated completely. In one previous genome-wide association study (GWAS) of SCZ in the Caucasian population, the QPCT has been reported as susceptible gene for SCZ. The QPCT gene encodes Glutaminyl cyclase (QC), an enzyme which is involved in the post translational modification by converting N-terminal glutamate of protein to pyroglutamate, which is resistant to protease degradation, more hydrophobic, and prone to aggregation and neurotoxic. To further investigate the role of this gene in the pathogenesis of schizophrenia in the Han Chinese population, we conducted this study in 1,248 (Mean age ± S.D, 36.44 years ± 9.0) SCZ cases, 1,248 (Mean age ± S.D, 30.62 years ± 11.35) healthy control samples for a case control study. We genotyped six SNPs in this study, including one positive SNP of the previous study, using the Sequenom MassARRAY platform. We found that rs2373000 was significantly associated with SCZ before correction [rs2373000: P allele = 0.016, χ(2) = 5.784, OR [95%CI] = 0.861 [0.762-0.972], P genotype = 0.018, χ(2) = 0.069]. After permutation correction for multiple testing, rs2373000 [rs2373000: P Allele corrected = 0.063, P genotype corrected = 0.069] showed marginal association with SCZ. Additionally, one pathogenic haplotype (TGT) containing rs2373000 was also significantly associated with SCZ. Our results are consistent with the findings of previous study and the genetic risk of QPCT gene for SCZ also exists in the Han Chinese population.

SNX29, a new susceptibility gene shared with major mental disorders in Han Chinese population.

OBJECTIVES: Environmental and genetic factors play important roles in the development of schizophrenia (SCZ), bipolar disorder (BPD) or major depressive disorder (MDD). Some risk loci are identified with shared genetic effects on major psychiatric disorders. To investigate whether SNX29 gene played a significant role in these psychiatric disorders in the Han Chinese population. METHODS: We focussed on 11 single-nucleotide polymorphisms (SNPs) harbouring SNX29 gene and carried out case-control studies in patients with SCZ (n = 1248), BPD (n = 1344), or MDD (n = 1056), and 1248 healthy controls (HC) recruited from the Han Chinese population. We constructed weighted gene co-expression network analysis (WGCNA) and extracted significant modules by R package. RESULTS: We found that rs3743592 was significantly associated with MDD and rs6498263 with BPD in both allele and genotype distributions. Before correction, rs3743592 showed allelic and genotypic significance with SCZ, rs6498263 showed allelic significance with SCZ. WGCNA identified top 10 modules of co-expressed genes. Gene Ontology (GO) and pathway analysis were used to examine the functions of SNX29, which revealed that SNX29 was involved in the regulation of a number of biological processes, such as TGF-beta, ErbB, and Wnt signalling pathway, etc. CONCLUSIONS: Our results supported common risk factors in SNX29 might share among these three mental disorders in the Han Chinese population.

Association between the variability of the ABCA13 gene and the risk of major depressive disorder and schizophrenia in the Han Chinese population.

OBJECTIVES: The ATP-binding cassette transporter superfamily is one of the largest membrane protein families, which is responsible for transportation of substances across the membranes by utilising energy. Some research has bridged the variations in ABCA13 with occurrence of psychiatric disorders. To investigate the overlapping risk conferred by ABCA13 for both major depressive disorder and schizophrenia, we analysed tag single nucleotide polymorphisms (tag SNPs). METHODS: We used TaqMan® technology to genotype 1045 major depressive disorder patients, 1235 schizophrenia patients and 1235 healthy controls of Han Chinese origin. RESULTS: We found that rs7789493 (Pallele = 7.23E-04, Pgenotype =.001) was associated with major depressive disorder, while rs17132388 (Pallele = 1.63E-04, Pgenotype = 7.50E-04) and rs6583476 (Pallele = 5.50E-04, Pgenotype =.002) showed statistically significant association with schizophrenia. CONCLUSIONS: Our results indicate that the ABCA13 gene may contain overlapping common genetic risk factors for both major depressive disorder and schizophrenia in the Han Chinese population. The study on variants conferring overlapping risk for multiple psychiatric disorders could be tangible pathogenesis support in clinical or diagnostic references.

A new risk locus in the ZEB2 gene for schizophrenia in the Han Chinese population.

The ZEB2 gene encodes the Zinc Finger E-box binding protein. As a key regulator of epithelial mesenchymal differentiation, ZEB2 plays an important role in the pathogenesis of cancer, and its high level expression has been observed in glioma patients. Different mutations in this gene have been identified in patients with Mowat-Wilson syndrome. A previous genome-wide association study (GWAS) of schizophrenia conducted in Caucasians has shown a significant association of rs12991836, located near the ZEB2 gene, with schizophrenia. Thus, we conducted a case control study to further investigate whether this genomic region is also a susceptibility locus for schizophrenia in the Han Chinese population. In total, 1248 schizophrenia (SCZ) cases (mean age±S.D., 36.44±9.0years), 1344 bipolar disorder (BPD) cases (mean age±S.D., 34.84±11.44years), 1056 major depressive disorder (MDD) cases (mean age±S.D., 34.41±12.09years) and 1248 healthy control samples (mean age±S.D., 30.62±11.35years) were recruited. We genotyped 12 SNPs using the Sequenom MassARRAY platform in this study. We found that rs6755392 showed a significant association with SCZ (rs6755392: adjusted Pallele=0.016; adjusted Pgenotype=0.052; OR (95% CI)=1.201 (1.073~1.344)). Additionally, two haplotypes (TCTG, TCTA) were also significantly associated with SCZ. This is the first study claiming the association of the genetic risks of rs6755392 in the ZEB2 gene with schizophrenia.

Analysis of association between common variants in the SLCO6A1 gene with schizophrenia, bipolar disorder and major depressive disorder in the Han Chinese population.

OBJECTIVES: The SLCO6A1 gene belongs to a superfamily of genes which is known to be a solute carrier family of OATPs (SLCO). The SLCO6A1 gene encodes OATP6A1 protein in humans. A previous genome-wide association study (GWAS) of schizophrenia conducted in the Swedish population demonstrated a significant association of rs6878284, which is located in the SLCO6A1 gene, with schizophrenia. To further investigate whether this gene is also a risk locus for schizophrenia (SCZ), bipolar disorder (BPD) and major depressive disorder (MDD) in the Han Chinese population, a case-control study was designed. METHODS: In total 1,248 unrelated SCZ cases, 1,344 BPD cases, 1,056 unrelated MDD cases and 1,248 normal controls were analysed in this study. We genotyped five SNPs using the Sequenom MassARRAY platform. RESULTS: We found no association of rs6878284 with SCZ [Corrected Pallele = 0.969, Corrected Pgenotype = 0.997]. Furthermore, we found a statistically significant association of the rs7734060 genotype with MDD after correction [rs7734060: Corrected Pallele = 0.114, Corrected Pgenotype = 0.036] in the Han Chinese population. CONCLUSIONS: This is the first study which reveals no association of rs6878284 with SCZ and also predicts that rs7734060 could be a risk locus for MDD in the Han Chinese population.

Polymorphisms in NRGN are associated with schizophrenia, major depressive disorder and bipolar disorder in the Han Chinese population.

BACKGROUND: The NRGN gene locates on 11q24 and encodes a postsynaptic protein kinase substrate that binds calmodulin in the absence of calcium. In a previous genome-wide association study of schizophrenia in the Caucasian population, rs12807809 of NRGN was found to be significantly associated with schizophrenia, moreover, it was further found to be associated with bipolar disorder. METHODS: We recruited 1248 schizophrenia cases, 1344 bipolar disorder cases, 1056 major depressive disorder cases, and 1248 healthy controls from Han Chinese population. Rs12807809 and another two tag SNPs of NRGN were genotyped and analyzed in three diseases respectively. A meta-analysis of rs12807809 was also conducted to verify its association with schizophrenia in Han Chinese population. RESULTS: Rs7113041 was associated with bipolar disorder (odds ratio, 95% confidence interval (OR, 95% CI)=1.194, 1.032-1.383; Pgenotype=0.0126), and rs12278912 was associated with major depressive disorder (OR, 95% CI=0.789, 0.673-0.924; Pallele=0.0102, Pgenotype=0.0399) after Bonferroni correction. The "GA" haplotype of rs7113041-rs12278912 was significantly associated with schizophrenia, major depressive disorder and bipolar disorder (corresponding P values were 2.85E-04, 3.00E-03, and 5.40E-04 after Bonferroni correction). LIMITATIONS: Despite the association between NRGN and psychoses we have found, we failed to validate the positive variant rs12807809, which was reported in the Caucasian genome-wide association study both in our single site association test and the meta-analysis. Functional studies are needed to illuminate the role of NRGN in the pathogenesis of these mental disorders. CONCLUSIONS: Our findings prove that NRGN is a shared susceptibility gene of schizophrenia, major depression and bipolar disorder in Han Chinese, and this might provide a new target for the diagnosis and treatment of these mental disorders.

Significant association of GRM7 and GRM8 genes with schizophrenia and major depressive disorder in the Han Chinese population.

Metabotropic glutamate receptor type 7 (GRM7) and type 8 (GRM8) are involved in the neurotransmission of glutamate which is supposed to play an important role in the development of schizophrenia (SCZ) and major depressive disorders (MDD). We designed this study to investigate whether common DNA variants or their genetic interactions within GRM7 and GMR8 genes were associated with these disorders in the Han Chinese population. Fourteen SNPs in GRM7 and GRM8 were selected within a sample set comprising 1235 SCZ patients, 1045 MDD patients and 1235 normal controls. Significant association in SCZ case-control subjects was observed for rs2229902 (permutated Pallele=0.0005, OR=1.492 [95% CI=1.231-1.807]) and rs9870680 (permutated Pallele=0.0023, OR=1.262 [95% CI=1.116-1.426]) in GRM7 and rs2237781 (permutated Pallele=0.0027, OR=1.346 [95% CI=1.149-1.575]) in GRM8. Association analysis for MDD case-control subjects revealed positive results in rs779706 (permutated Pallele=0.0099, OR=1.237 [95% CI=1.093-1.399]) of GRM7 and in rs1361995 (permutated Pallele=0.0017, OR=1.488 [95% CI=1.215-1.823]) of GRM8. Moreover, a three-locus model, constituted by polymorphisms in GRM7 and GRM8 significantly correlated with MDD in the gene-gene interaction analysis. Meta-analysis and haplotype analysis further confirmed our significant results. We demonstrated the genetic association of GRM7 and GRM8 with SCZ and MDD in the Han Chinese population. We also found susceptibility interactive effects of these two genes with both psychiatric disorders, which might provide new insights into the etiology of them.