Jue Ji

Common variants on 8p12 and 1q24.2 confer risk of schizophrenia

Schizophrenia is a severe mental disorder affecting ∼1% of the world population, with heritability of up to 80%. To identify new common genetic risk factors, we performed a genome-wide association study (GWAS) in the Han Chinese population. The discovery sample set consisted of 3,750 individuals with schizophrenia and 6,468 healthy controls (1,578 cases and 1,592 controls from northern Han Chinese, 1,238 cases and 2,856 controls from central Han Chinese, and 934 cases and 2,020 controls from the southern Han Chinese). We further analyzed the strongest association signals in an additional independent cohort of 4,383 cases and 4,539 controls from the Han Chinese population. Meta-analysis identified common SNPs that associated with schizophrenia with genome-wide significance on 8p12 (rs16887244, P = 1.27 × 10−10) and 1q24.2 (rs10489202, P = 9.50 × 10−9). Our findings provide new insights into the pathogenesis of schizophrenia.

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.

A genome-wide association study reveals association between common variants in an intergenic region of 4q25 and high-grade myopia in the Chinese Han population

High-grade myopia (HM) is highly heritable, and has a high prevalence in the Han Chinese population. We carried out a genome-wide association study involving 102 HM cases suffering from retinal degeneration, and 335 controls who were free from HM and fundus diseases. Significant single-nucleotide polymorphisms were replicated in two follow-up studies: stage I involved 2628 independent cases and 9485 controls, and stage II involved a further 263 cases and 586 HM-free controls. The results were combined in a meta-analysis. Cases and controls were drawn from the Chinese Han population. A locus in an intergenic region at 4q25, within MYP11 (4q22-q27, OMIM: 609994), was found to be associated with HM (rs10034228, P(meta) = 7.70 × 10(-13), allelic odds ratio = 0.81, 95% confidence interval 0.76-0.86). There are no known genes in the region but a number of expressed sequence tags (ESTs) have been located there, one of which (BI480957) has been reported to express in the native human retinal pigment epithelium. In addition, a predicted gene was identified in this region. The genes predicted protein sequence is highly similar to tubulin, beta 8 and beta-tubulin 4Q. Several previous studies have shown that tubulin plays an important role in eye development. Our result is compatible with a previous linkage study in the Han Chinese population (mapping in MYP11, 4q22-q27), and provides a more accurate locus for HM. Although there is insufficient evidence to indicate that expressed EST and the predicted gene play an important role in developing HM, this region merits further study as a candidate for the disease.

CACNA1C, schizophrenia and major depressive disorder in the Han Chinese population

BACKGROUND Common psychiatric disorders are highly heritable, indicating that genetic factors play an important role in their aetiology. The CACNA1C gene, which codes for subunit alpha-1C of the Cav1.2 voltage-dependent L-type calcium channel, has been consistently found to be the shared risk gene for several kinds of mental disorder. AIMS To investigate whether CACNA1C is a susceptibility gene for schizophrenia and major depressive disorder in the Han Chinese population. METHOD We carried out a case-control study of 1235 patients with schizophrenia, 1045 with major depressive disorder and 1235 healthy controls. A tag single nucleotide polymorphism (SNP) rs1006737 along with another 10 tag SNPs in the CACNA1C gene were genotyped in all samples. RESULTS We found that rs1006737 was associated with both schizophrenia (P(allele) = 0.0014, P(genotype) = 0.006, odds ratio (OR) = 1.384, 95% CI 1.134-1.690) and major depressive disorder (P(allele) = 0.0007, P(genotype) = 0.003, OR = 1.425, 95% CI 1.160-1.752). CONCLUSIONS Our findings support CACNA1C being a risk gene for both schizophrenia and major depressive disorder in the Han Chinese population.

Rare CNVs and Tag SNPs at 15q11.2 Are Associated With Schizophrenia in the Han Chinese Population

BACKGROUND Rare copy number variations (CNVs) were involved in the etiology of neuropsychiatric disorders, and some of them appeared to be shared risk factors for several different diseases. One of those promising loci is the CNV at 15q11.2, including 4 genes, TUBGCP5, CYFIP1, NIPA2, and NIPA1. Several studies showed that microdeletions at this locus were significant associated with schizophrenia. In the current study, we investigated the role of both rare CNVs and common single nucleotide polymorphisms (SNPs) at 15q11.2 in schizophrenia in the Chinese Han population. METHODS We screened deletions at 15q11.2 in 2058 schizophrenia patients and 3275 normal controls in Chinese Han population by Affymetrix 500K/6.0 SNP arrays and SYBR green real-time polymerase chain reaction and then validated deletions by multiplex ligation-dependent probe amplification and Taqman real-time assays. We successfully genotyped 27 tag SNPs in total and tested associations in 1144 schizophrenia cases and 1144 normal controls. RESULTS We found a triple increase of deletions in cases over controls, with OR=4.45 (95% CI=1.36-14.60) and P=.014. In the analysis of common SNPs, we found that the most significant SNP in schizophrenia was rs4778334 (OR=.72, 95% CI=0.60-0.87, allelic P=.0056 after permutation, genotypic P=.015 after permutation). We also found SNP rs1009153 in CYFIP1 was associated with schizophrenia (OR=0.82, 95% CI=0.73-0.93, allelic P=.044 after permutation). CONCLUSION We found that both rare deletions and common variants at 15q11.2 were associated with schizophrenia in the Chinese Han population.

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.

Genome-wide association analysis identifies three new risk loci for gout arthritis in Han Chinese

Gout is one of the most common types of inflammatory arthritis, caused by the deposition of monosodium urate crystals in and around the joints. Previous genome-wide association studies (GWASs) have identified many genetic loci associated with raised serum urate concentrations. However, hyperuricemia alone is not sufficient for the development of gout arthritis. Here we conduct a multistage GWAS in Han Chinese using 4,275 male gout patients and 6,272 normal male controls (1,255 cases and 1,848 controls were genome-wide genotyped), with an additional 1,644 hyperuricemic controls. We discover three new risk loci, 17q23.2 (rs11653176, P=1.36 × 10−13, BCAS3), 9p24.2 (rs12236871, P=1.48 × 10−10, RFX3) and 11p15.5 (rs179785, P=1.28 × 10−8, KCNQ1), which contain inflammatory candidate genes. Our results suggest that these loci are most likely related to the progression from hyperuricemia to inflammatory gout, which will provide new insights into the pathogenesis of gout arthritis.

Association between a COMT polymorphism and clinical response to risperidone treatment: a pharmacogenetic study.

A total of 130 Chinese schizophrenic patients (45 male, 85 female) were enrolled in the study. Clinical efficacy was determined using Brief Psychiatric Rating Scale (BPRS) scores. We genotyped 10 single-nucleotide polymorphisms (SNPs) of the catechol-O-methyl transferase gene (COMT) in our patients and re-examined them for association with changes in BPRS scores after 8 weeks of risperidone monotherapy. COMT is one of the genes that confer susceptibility to schizophrenia, both because of its role in neurotransmitter metabolism and because of its location in the high-risk schizophrenia-related region 22q11. Recent studies also found that COMT functional polymorphisms influenced individual response to antipsychotic medication. Our aim in this study was to explore the influence of COMT polymorphisms on pharmacological response to risperidone in the Chinese population. Statistical analysis revealed a significant association between an upstream COMT SNP, rs9606186, and scores reduction of BPRS in all patients and in the male subgroup but not in the female subgroup (allele analysis: P=0.055 for all, P=0.012 for male patients; genotype analysis: P=0.046 for all, P=0.020 for male patients, uncorrected, odds ratio=3.95). The COMT gene polymorphism, SNP rs9606186, is associated with risperidone therapy efficiency in the Chinese population. This association exhibited a sexually dimorphic difference, which may shed light on the genetics of COMT and its enzymatic sex-dependent mechanism.

CTLA-4 confers a risk of recurrent schizophrenia, major depressive disorder and bipolar disorder in the Chinese Han population.

Previous studies have reported that the cytotoxic T lymphocyte antigen-4 (CTLA-4) gene, which is related to immunological function such as T-cell regulation, is associated with psychiatric disorders. In this study, we studied the relationship between CTLA-4 and three major psychiatric disorders, schizophrenia, major depressive disorder and bipolar disorder in the Chinese Han population. We recruited 1140 schizophrenia patients, 1140 major depressive disorder patients, 1140 bipolar disorder patients, and 1140 normal controls to examine the risk conferred by 6 tag SNPs (rs231777, rs231775, rs231779, rs3087243, rs5742909, rs16840252) in the CTLA-4 gene. We found that rs231779 conferred a risk for schizophrenia (P(allele)=0.0003, P(genotype)=0.0016), major depressive disorder (P(allele)=0.0006, P(genotype)=0.0026) and bipolar disorder (P(allele)=0.0004, P(genotype)=0.0018). In addition, rs231777 and rs16840252 had a significant association with schizophrenia (rs231777: P(allele)=0.0201, rs16840252: P(allele)=0.0081, P(genotype)=0.0117), and rs231777 had significant association with bipolar disorder (rs231777: P(allele)=0.0199). However, after 10,000 permutations, only rs231779 remained significant (schizophrenia: P(allele)=0.0010, P(genotype)=0.0145, major depressive disorder: P(allele)=0.0010, P(genotype)=0.0201, bipolar disorder: P(allele)=0.0008, P(genotype)=0.0125). Our results suggest that shared common risk factors for schizophrenia, major depressive disorder and bipolar disorder exist in the CTLA-4 gene in the Chinese Han population.

No association between EGR gene family polymorphisms and schizophrenia in the Chinese population

Early growth response (EGR) genes are thought to have a role in the pathogenesis of schizophrenia because of their conserved DNA binding domain and biologically activity in neuronal plasticity. This zinc-finger motif could influence gene post-translational modification and expression. The multigenetic association model, using markers in genes of similar or antagonistic biological effects within a signal pathway or gene family, might be more appropriate to this aspect of the schizophrenia hypothesis than the single gene strategy. In this study we investigated the role of EGR1, EGR2, EGR3 and EGR4 within the EGR family. Taqman technology was used to examine 12 single nucleotide polymorphisms (SNPs) covering these four genes in 2044 Chinese Han subjects. Case-control analyses were performed to detect association of these 4 genes with schizophrenia and multifactor dimensionality reduction (MDR) analysis was employed to examine their potential gene-gene interaction in schizophrenia. Neither allelic nor genotypic single-locus tests revealed any significant association between EGR1-4 and the risk of schizophrenia nor was any such association found with regard to interaction within EGR1-4 (p(min)=0.623, CV Consistency=10/10). We concluded that although multiple candidate genes are involved in schizophrenogenic development, the EGR family may not play a major role in schizophrenia susceptibility in the Chinese Han population.