Zujia Wen

GWAS Identifies Novel Susceptibility Loci on 6p21.32 and 21q21.3 for Hepatocellular Carcinoma in Chronic Hepatitis B Virus Carriers

Genome-wide association studies (GWAS) have recently identified KIF1B as susceptibility locus for hepatitis B virus (HBV)–related hepatocellular carcinoma (HCC). To further identify novel susceptibility loci associated with HBV–related HCC and replicate the previously reported association, we performed a large three-stage GWAS in the Han Chinese population. 523,663 autosomal SNPs in 1,538 HBV–positive HCC patients and 1,465 chronic HBV carriers were genotyped for the discovery stage. Top candidate SNPs were genotyped in the initial validation samples of 2,112 HBV–positive HCC cases and 2,208 HBV carriers and then in the second validation samples of 1,021 cases and 1,491 HBV carriers. We discovered two novel associations at rs9272105 (HLA-DQA1/DRB1) on 6p21.32 (OR = 1.30, P = 1.13×10−19) and rs455804 (GRIK1) on 21q21.3 (OR = 0.84, P = 1.86×10−8), which were further replicated in the fourth independent sample of 1,298 cases and 1,026 controls (rs9272105: OR = 1.25, P = 1.71×10−4; rs455804: OR = 0.84, P = 6.92×10−3). We also revealed the associations of HLA-DRB1*0405 and 0901*0602, which could partially account for the association at rs9272105. The association at rs455804 implicates GRIK1 as a novel susceptibility gene for HBV–related HCC, suggesting the involvement of glutamate signaling in the development of HBV–related HCC.

Recurrent gain-of-function USP8 mutations in Cushing's disease

Cushings disease, also known as adrenocorticotropic hormone (ACTH)-secreting pituitary adenomas (PAs) that cause excess cortisol production, accounts for up to 85% of corticotrophin-dependent Cushings syndrome cases. However, the genetic alterations in this disease are unclear. Here, we performed whole-exome sequencing of DNA derived from 12 ACTH-secreting PAs and matched blood samples, which revealed three types of somatic mutations in a candidate gene, USP8 (encoding ubiquitin-specific protease 8), exclusively in exon 14 in 8 of 12 ACTH-secreting PAs. We further evaluated somatic USP8 mutations in additional 258 PAs by Sanger sequencing. Targeted sequencing further identified a total of 17 types of USP8 variants in 67 of 108 ACTH-secreting PAs (62.04%). However, none of these mutations was detected in other types of PAs (n = 150). These mutations aggregate within the 14-3-3 binding motif of USP8 and disrupt the interaction between USP8 and 14-3-3 protein, resulting in an elevated capacity to protect EGFR from lysosomal degradation. Accordingly, PAs with mutated USP8 display a higher incidence of EGFR expression, elevated EGFR protein abundance and mRNA expression levels of POMC, which encodes the precursor of ACTH. PAs with mutated USP8 are significantly smaller in size and have higher ACTH production than wild-type PAs. In surgically resected primary USP8-mutated tumor cells, USP8 knockdown or blocking EGFR effectively attenuates ACTH secretion. Taken together, somatic gain-of-function USP8 mutations are common and contribute to ACTH overproduction in Cushings disease. Inhibition of USP8 or EGFR is promising for treating USP8-mutated corticotrophin adenoma. Our study highlights the potentially functional mutated gene in Cushings disease and provides insights into the therapeutics of this disease.

Genome-wide association analysis identifies 30 new susceptibility loci for schizophrenia

We conducted a genome-wide association study (GWAS) with replication in 36,180 Chinese individuals and performed further transancestry meta-analyses with data from the Psychiatry Genomics Consortium (PGC2). Approximately 95% of the genome-wide significant (GWS) index alleles (or their proxies) from the PGC2 study were overrepresented in Chinese schizophrenia cases, including ∼50% that achieved nominal significance and ∼75% that continued to be GWS in the transancestry analysis. The Chinese-only analysis identified seven GWS loci; three of these also were GWS in the transancestry analyses, which identified 109 GWS loci, thus yielding a total of 113 GWS loci (30 novel) in at least one of these analyses. We observed improvements in the fine-mapping resolution at many susceptibility loci. Our results provide several lines of evidence supporting candidate genes at many loci and highlight some pathways for further research. Together, our findings provide novel insight into the genetic architecture and biological etiology of schizophrenia.

CNTNAP2 is significantly associated with schizophrenia and major depression in the Han Chinese population.

CNTNAP2, located on 7q35-36.1, encodes a single-pass transmembrane protein mediating cell-cell interactions in the nervous system. CNTNAP2 has been suggested to play an important role in mental diseases such as autism and language disorder. However, we still do not know whether it also confers risk to major psychiatric disorders such as schizophrenia, major depression and bipolar disorder. We analysed single nucleotide polymorphisms (SNPs) previously reported to be associated with autism or language impairment in 1135 schizophrenia patients, 1135 unrelated major depression patients, 1135 unrelated bipolar disorder patients and 1135 unrelated normal controls recruited from the Han Chinese population. We found that the genotypes of rs17236239 were significantly associated with schizophrenia and the alleles of rs2710102 and rs2710117 were significantly associated with major depression. According to the location of significant signals, our study indicated that exon 13-15 of CNTNAP2 may play important roles in both schizophrenia and major depression in the Han Chinese population.

The GSK3B gene confers risk for both major depressive disorder and schizophrenia in the Han Chinese population

BACKGROUND Glycogen synthease kinase-3B is a key gene encoding a protein kinase which is abundant in brain, and is involved in signal transduction cascades of neuronal cell development and energy metabolism. Previous researches proposed GSK3B as a potential region for schizophrenia. METHOD To validate the susceptibility of GSK3B to major depressive disorder, and to investigate the overlapping risk conferred by GSK3B for mental disorders, we performed a large-scale case-control study, analyzed 6 tag single nucleotide polymorphisms using TaqMan® technology in 1,045 major depressive disorder patients, 1,235 schizophrenia patients and 1,235 normal controls of Han Chinese origin. RESULTS We found rs334535 (Pallele=2.79E-03, Pgenotype=5.00E-03, OR=1.429) and rs2199503 (Pallele=0.020, Pgenotype= 0.040, OR=1.157) showed association with major depressive disorder before Bonferroni correction. rs6771023 (adjusted Pallele=1.64E-03, adjusted Pgenotype=6.00E-03, OR=0.701) and rs2199503 (adjusted Pallele=0.001, adjusted Pgenotype=0.002, OR=1.251) showed significant association with schizophrenia after Bonferroni correction. rs2199503 (adjusted Pallele=1.70E-03, adjusted Pgenotype=0.006, OR=1.208) remained to be significant in the combined cases of major depressive disorder and schizophrenia after Bonferroni correction. LIMITATIONS Further validations of our findings in samples with larger scale are suggested, and functional genomic study is needed to elucidate the role of GSK3B in signal pathway and psychiatric disorders. CONCLUSIONS Our results provide evidence that the GSK3B gene could be a promising region which contains genetic risk 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 and clinical or diagnostic references.

Comparison of the performance of Ion Torrent chips in noninvasive prenatal trisomy detection.

Semiconductor high-throughput sequencing, represented by Ion Torrent PGM/Proton, proves to be feasible in the noninvasive prenatal diagnosis of fetal aneuploidies. It is commendable that, with less data and relevant cost also, an accurate result can be achieved owing to the high sensitivity and specificity of such kind of technology. We conducted a comparative analysis of the performance of four different Ion chips in detecting fetal chromosomal aneuploidies. Eight maternal plasma DNA samples, including four pregnancies with normal fetuses and four with trisomy 21 fetuses, were sequenced on Ion Torrent 314/316/318/PI chips, respectively. Results such as read mapped ratio, correlation coefficient and phred quality score were calculated and parallelly compared. All samples were correctly classified even with low-throughput chip, and, among the four chips, the 316 chip had the highest read mapped ratio, correlation coefficient, mean read length and phred quality score. All chips were well consistent with each other. Our results showed that all Ion chips are applicable in noninvasive prenatal fetal aneuploidy diagnosis. We recommend researchers or clinicians to use the appropriate chip with barcoding technology on the basis of the sample number.

Genome-wide Analysis of the Role of Copy Number Variation in Schizophrenia Risk in Chinese

BACKGROUND Compelling evidence suggested the role of copy number variations (CNVs) in schizophrenia susceptibility. Most of the evidence was from studies in populations with European ancestry. We tried to validate the associated CNV loci in a Han Chinese population and identify novel loci conferring risk of schizophrenia. METHODS We performed a genome-wide CNV analysis on 6588 patients with schizophrenia and 11,904 control subjects of Han Chinese ancestry. RESULTS Our data confirmed increased genome-wide CNV (>500 kb and <1%) burden in schizophrenia, and the increasing trend was more significant when only >1 Mb CNVs were considered. We also replicated several associated loci that were previously identified in European populations, including duplications at 16p11.2, 15q11.2-13.1, 7q11.23, and VIPR2 and deletions at 22q11.2, 1q21.1-q21.2, and NRXN1. In addition, we discovered three additional new potential loci (odds ratio >6, p < .05): duplications at 1p36.32, 10p12.1, and 13q13.3, involving many neurodevelopmental and synaptic related genes. CONCLUSIONS Our findings provide further support for the role of CNVs in the etiology of schizophrenia.

Common variants at 10p12.31, 10q21.1 and 13q12.13 are associated with sporadic pituitary adenoma

Pituitary adenoma is one of the most common intracranial neoplasms, and its genetic basis remains largely unknown. To identify genetic susceptibility loci for sporadic pituitary adenoma, we performed a three-stage genome-wide association study (GWAS) in the Han Chinese population. We first analyzed genome-wide SNP data in 771 pituitary adenoma cases and 2,788 controls and then carried forward the promising variants for replication in another 2 independent sets (2,542 cases and 3,620 controls in total). We identified three new susceptibility loci below the genome-wide significance threshold (P < 5 × 10−8) in the combined analyses: 10p12.31 (rs2359536, Pmeta = 2.25 × 10−10 and rs10828088, Pmeta = 6.27 × 10−10), 10q21.1 (rs10763170, Pmeta = 6.88 × 10−10) and 13q12.13 (rs17083838, Pmeta = 1.89 × 10−8). This study is the first GWAS to our knowledge on sporadic pituitary adenoma, and our results provide insight into the genetic basis of this disease.

Genetic association of ACSM1 variation with schizophrenia and major depressive disorder in the Han Chinese population

Schizophrenia (SCZ) and major depressive disorder (MDD) are two of the most common and severe mental disorders, the etiologies of which are not yet clearly elucidated. The ACSM1 gene has been identified as a susceptibility gene for SCZ in two previous genome‐wide association studies (GWAS). ACSM1 catalyzes the activation of fatty acids and plays an important role in the metabolic system. Some evidence has suggested that ACSM1 contributes to a genetic risk for MDD. The present study aimed to evaluate the common genetic risk of the ACSM1 gene in these two disorders in the Han Chinese population. In total, 1235 patients with SCZ, 1045 patients with MDD and 1235 control subjects of Chinese origin were recruited. Six single nuclear polymorphisms (SNPs) in ACSM1 were genotyped to test their associations with SCZ and MDD. SNP rs163234 was found to be significantly associated with both SCZ (permutated Pallele = 1.700 × 10−3, OR = 1.350 [95% CI = 1.152–1.581]) and MDD (permutated Pallele = 4.800 × 10−3, OR = 1.329 [95% CI = 1.127–1.567]). SNP rs433598 showed a strong association with SCZ (permutated Pallele = 4.300 × 10−3, OR = 1.303 [95% CI = 1.117–1.520]). Haplotype analysis of the blocks containing the two positive markers also revealed a significant association. This is the first study to assess the possible association of the ACSM1 gene with a genetic susceptibility for MDD. Our data are the first to suggest a positive association of the ACSM1 gene with a genetic susceptibility for SCZ and MDD in the Han Chinese population.

ITIH family genes confer risk to schizophrenia and major depressive disorder in the Han Chinese population.

As a major extracellular matrix component, ITIHs played an important role in inflammation and carcinogenesis. Several genome-wide association studies have reported that some positive signals which were derived from the tight linkage disequilibrium region on chromosome 3p21 were associated with both schizophrenia and bipolar disorders in the Caucasian population. To further investigate whether this genomic region is also a susceptibility locus of schizophrenia and major depressive disorder in the Han Chinese population, we conducted this study by recruiting 1235 schizophrenia patients, 1045 major depressive disorder patients and 1235 healthy control subjects in the Han Chinese samples for a case-control study. We genotyped seven SNPs within this region using TaqMan® technology. We found that rs2710322 was significantly associated with schizophrenia (adjusted P(allele) = 0.0018, adjusted P(genotype) = 0.006, OR [95% CI] = 1.278 [1.117-1.462]) while rs1042779 was weakly associated with schizophrenia (adjusted P(allele) = 0.048, OR [95% CI] = 1.164 [1.040-1.303]) and major depressive disorder (adjusted P(allele) = 0.042, OR [95% CI] = 1.178 [1.047-1.326]); it was also our finding that rs3821831 was positively associated with major depressive disorder (adjusted P(allele) = 0.003, adjusted P(genotype) = 0.006, OR [95% CI] = 1.426 [1.156-1.760]). Furthermore, no haplotype was found to be associated with schizophrenia and major depressive disorder. Via the association analysis which combines the schizophrenia and major depressive disorder cases, we also notice that rs1042779 and rs3821831 were significantly associated with combined cases (rs1042779: adjusted P(allele) = 0.012, adjusted P(genotype) = 0.018, OR [95% CI] = 1.171 [1.060-1.292]; rs3821831:adjusted P(genotype) = 0.012, OR [95% CI] = 1.193 [1.010-1.410]). Our results revealed that the shared genetic risk factors of both schizophrenia and major depressive disorder exist in ITIH family genes in the Han Chinese population.