Voltage-gated calcium channel activity and complex related genes and schizophrenia: A systematic investigation based on Han Chinese population

GRM7 deficiency, from excitotoxicity and neuroinflammation to neurodegeneration: Systematic review of GRM7 deficient patients

The metabotropic glutamate receptor 7 (mGluR7) is a presynaptic G-protein-coupled glutamate receptor that modulates neurotransmitter release and synaptic plasticity at presynaptic terminals. It is encoded by GRM7, and recently variants have been identified in patients with autism spectrum disorder (ASD), attention deficit hyperactivity disorder (ADHD), developmental delay (DD), intellectual disability (ID), and brain malformations. To gain updated insights into the function of GRM7 and the phenotypic spectrum of genetic variations within this gene, we conducted a systematic review of relevant literature utilizing PubMed, Web of Science, and Scopus databases. Among the 14 articles meeting the inclusion criteria, a total of 42 patients (from 28 families) harboring confirmed mutations in the GRM7 gene have been documented. Specifically, there were 17 patients with heterozygous mutations, 20 patients with homozygous mutations, and 5 patients with compound heterozygous mutations. Common clinical features included intellectual behavioral disability, seizure/epilepsy, microcephaly, developmental delay, peripheral hypertonia and hypomyelination. Genotype-phenotype correlation was not clear and each variant had unique characteristics including gene dosage, mutant protein surface expression, and degradation pathway that result with a spectrum of phenotype manifestations through ASD or ADHD to severe DD/ID with brain malformations. Neuroinflammation may play a role in the development and/or progression of GRM7-related neurodegeneration along with excitotoxicity. The clinical and functional data presented here demonstrate that both autosomal dominant and recessive inheritance of GRM7 mutation can cause disease spectrum phenotypes through ASD or ADHD to severe DD/ID and seizure with brain malformations.

New insights into the physiology and pathophysiology of the atypical sodium leak channel NALCN

Cell excitability and its modulation by hormones and neurotransmitters involve the concerted action of a large repertoire of membrane proteins, especially ion channels. Unique complements of coexpressed ion channels are exquisitely balanced against each other in different excitable cell types, establishing distinct electrical properties that are tailored for diverse physiological contributions, and dysfunction of any component may induce a disease state. A crucial parameter controlling cell excitability is the resting membrane potential (RMP) set by extra- and intracellular concentrations of ions, mainly Na+, K+, and Cl-, and their passive permeation across the cell membrane through leak ion channels. Indeed, dysregulation of RMP causes significant effects on cellular excitability. This review describes the molecular and physiological properties of the Na+ leak channel NALCN, which associates with its accessory subunits UNC-79, UNC-80, and NLF-1/FAM155 to conduct depolarizing background Na+ currents in various excitable cell types, especially neurons. Studies of animal models clearly demonstrate that NALCN contributes to fundamental physiological processes in the nervous system including the control of respiratory rhythm, circadian rhythm, sleep, and locomotor behavior. Furthermore, dysfunction of NALCN and its subunits is associated with severe pathological states in humans. The critical involvement of NALCN in physiology is now well established, but its study has been hampered by the lack of specific drugs that can block or agonize NALCN currents in vitro and in vivo. Molecular tools and animal models are now available to accelerate our understanding of how NALCN contributes to key physiological functions and the development of novel therapies for NALCN channelopathies.

A randomized controlled trial of Vitamin D supplementation in Iranian patients with schizophrenia: Effects on serum levels of glycogen synthase kinase-3β and symptom severity

BACKGROUND

Growing evidence has shown that hypovitaminosis D is a risk factor for developing schizophrenia and comorbid conditions. Therefore, this study aimed to examine the effect of vitamin D supplementation on serum levels of vitamin D, metabolic factors related to insulin resistance (IR) and the severity of the disorder in patients with schizophrenia.

METHODS

Forty-eight chronic male patients with schizophrenia with vitamin D deficiency (≤20 ng/mL= (≤50 nmol/l) were selected and randomly assigned to vitamin D treatment and placebo groups. Subjects were supplemented for 8 weeks with vitamin D (2000 IU/day) or placebo.

RESULTS

Within-group comparison revealed that the vitamin D group had a significant reduction in waist circumference, Positive and Negative Syndrome Scale - total score (PANSS-TS), and glycogen synthase kinase 3 beta (GSK-3β) levels (P = .022, P = <.001 and P = .013, respectively). On the other hand, the placebo group showed a significant increase in the level of fasting serum insulin and Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) (P = .003 and P = .003). The between-group comparison showed a significant difference in terms of PANSS-TS, GSK-3β, fasting serum insulin (FSI), and HOMA-IR (P = .022, P = .048, P = .013 and P = .014 respectively).

CONCLUSIONS

Among vitamin D deficient patients with schizophrenia, vitamin D supplementation may affect GSK-3 β, an important biomarker in schizophrenia and insulin resistance. In addition, vitamin D supplementation in such patients may reduce the disorder's symptom severity.

Ethnicity-dependent effect of rs1799971 polymorphism on OPRM1 expression in the postmortem brain and responsiveness to antipsychotics

Schizophrenia is associated with aberration of inhibitory neurons. Although the mu-opioid receptor (MOR) is an essential modulator of inhibitory neurons, the effect of rs1799971 polymorphism in the MOR gene on risk of schizophrenia is controversial. Moreover, the disturbance of opioids systems in patients with schizophrenia has not been fully examined. We firstly conducted preliminary meta-analyses integrating Asian and European populations separately over 12,000 subjects to assess the effect of rs1799971 on risk of schizophrenia. Based on the above result, we also investigated the effect on the expression levels of MOR mRNA in the prefrontal cortex (PFC) and caudate nucleus of 41 postmortem brains. In addition, we determined whether these levels were related to antemortem schizophrenia symptoms and pharmacotherapeutic effects. The rs1799971 G-allele reduced the risk of schizophrenia in Asian populations (OR: 0.56, 95%CI: 0.32-0.98, p = 0.042) but increased it in European populations (OR: 1.66, 95%CI: 1.08-2.56, p = 0.022). It decreased MOR mRNA levels in PFC in the Japanese population (p = 0.031). Increased MOR mRNA level in PFC correlated with higher total score of antemortem schizophrenia symptoms (p = 0.017). Furthermore, the pharmacotherapeutic effect of first-generation antipsychotics was higher for genotype AA than AG/GG of rs1799971 (p = 0.036). The rs1799971 affects risk of schizophrenia and MOR mRNA expression and the effect varies according to ethnicity. Overexpression of MOR might induce severe schizophrenia symptoms. Therefore, MOR modulation may be the key clue for treating antipsychotics-resistant schizophrenia, and genotyping rs1799971 may provide a better pharmacotherapeutic strategy.

Pathophysiological Roles of Auxiliary Calcium Channel α2δ Subunits

α2δ proteins serve as auxiliary subunits of voltage-gated calcium channels, which are essential components of excitable cells such as skeletal and heart muscles, nerve cells of the brain and the peripheral nervous system, as well as endocrine cells. Over the recent years, α2δ proteins have been identified as critical regulators of synaptic functions, including the formation and differentiation of synapses. These functions require signalling mechanisms which are partly independent of calcium channels. Hence, in light of these features it is not surprising that the genes encoding for the four α2δ isoforms have recently been linked to neurological and neurodevelopmental disorders including epilepsy, autism spectrum disorders, schizophrenia, and depressive and bipolar disorders. Despite the increasing number of identified disease-associated mutations, the underlying pathophysiological mechanisms are only beginning to emerge. However, a thorough understanding of the pathophysiological role of α2δ proteins ideally serves two purposes: first, it will contribute to our understanding of general pathological mechanisms in synaptic disorders. Second, it may support the future development of novel and specific treatments for brain disorders. In this context, it is noteworthy that the antiepileptic and anti-allodynic drugs gabapentin and pregabalin both act via binding to α2δ proteins and are among the top sold drugs for treating neuropathic pain. In this book chapter, we will discuss recent developments in our understanding of the functions of α2δ proteins, both as calcium channel subunits and as independent regulatory entities. Furthermore, we present and summarize recently identified and likely pathogenic mutations in the genes encoding α2δ proteins and discuss potential underlying pathophysiological consequences at the molecular and structural level.

An Integrative Analysis of Identified Schizophrenia-Associated Brain Cell Types and Gene Expression Changes

Schizophrenia (SCZ) is a severe mental disorder that may result in hallucinations, delusions, and extremely disordered thinking. How each cell type in the brain contributes to SCZ occurrence is still unclear. Here, we leveraged the human dorsolateral prefrontal cortex bulk RNA-seq data, then used the RNA-seq deconvolution algorithm CIBERSORTx to generate SCZ brain single-cell RNA-seq data for a comprehensive analysis to understand SCZ-associated brain cell types and gene expression changes. Firstly, we observed that the proportions of brain cell types in SCZ differed from normal samples. Among these cell types, astrocyte, pericyte, and PAX6 cells were found to have a higher proportion in SCZ patients (astrocyte: SCZ = 0.163, control = 0.145, P.adj = 4.9 × 10^-4, effect size = 0.478; pericyte: SCZ = 0.057, control = 0.066, P.adj = 1.1 × 10^-4, effect size = 0.519; PAX6: SCZ = 0.014, control = 0.011, P.adj = 0.014, effect size = 0.377), while the L5/6_IT_CAR3 cells and LAMP5 cells are the exact opposite (L5/6_IT_Car3: SCZ = 0.102, control = 0.108, P.adj = 0.016, effect size = 0.369; LAMP5: SCZ = 0.057, control = 0.066, P.adj = 2.2 × 10^-6, effect size = 0.617). Next, we investigated gene expression in cell types and functional pathways in SCZ. We observed chemical synaptic transmission dysregulation in two types of GABAergic neurons (PVALB and LAMP5), and immune reaction involvement in GABAergic neurons (SST) and non-neuronal cell types (endothelial and oligodendrocyte). Furthermore, we observed that some differential expression genes from bulk RNA-seq displayed cell-type-specific abnormalities in the expression of molecules in SCZ. Finally, the cell types with the SCZ-related transcriptomic changes could be considered to belong to the same module since we observed two major similar coordinated transcriptomic changes across these cell types. Together, our results offer novel insights into cellular heterogeneity and the molecular mechanisms underlying SCZ.

Common variants of RARRES2 and RETN contribute to susceptibility to hand osteoarthritis and related pain

Aim: To examine the relationship of the RETN and RARRES2 genes with hand osteoarthritis (HOA) susceptibility risk, clinical severity and pain. Methods: A total of 3740 subjects comprising 1180 participants with HOA and 2560 controls were enrolled. Genetic association was evaluated at both single marker and haplotype levels using PLINK. Results: Two significant hits, single-nucleotide polymorphism (SNP) rs4721 from RARRES2 and SNP rs3745368 from RETN, were identified as being related to an increased risk of HOA. Significant associations were obtained for SNP rs3745368 with Kellgren-Lawrence grade in HOA patients and SNP rs4721 with pain analog scales of HOA patients. Conclusion: The authors' results indicate that RARRES2 and RETN affect HOA risk and are associated with clinical features and severity in patients with HOA.

Relationship between the early repolarization pattern and a history of suicide attempts among drug-free psychiatric patients

Aim

Suicide attempts are an important severe psychiatric symptom and a clear outcome for mental disorders. Although the relationship between the early repolarization pattern in electrocardiogram and psychiatric disorders has recently been reported, these reports have not been able to exclude the influence of psychiatric drugs. This study aimed to investigate the relationship between the early repolarization pattern and a history of suicide attempts among patients not receiving psychiatric medication.

Methods

A total of 71 patients with a history of suicide attempts were investigated, 38 of whom were analyzed for this study. We compared the frequency of the early repolarization pattern between a suicide attempt group and a control group. Then, we investigated the association between the early repolarization pattern and the suicide attempt group by logistic regression analysis, including electrocardiographic findings associated with psychiatric disorders.

Results

The findings indicated that the frequency of the early repolarization pattern was significantly higher in the suicide attempt group (n = 20; 52.6%) than in the control group (n = 4; 10.5%) (P < 0.001), and the results of the logistic regression analysis indicated that the early repolarization pattern was associated with suicide attempts.

Conclusions

These findings suggest that the early repolarization pattern is associated with a history of suicide attempts.

A genome-wide association study of suicide attempts in the million veterans program identifies evidence of pan-ancestry and ancestry-specific risk loci

To identify pan-ancestry and ancestry-specific loci associated with attempting suicide among veterans, we conducted a genome-wide association study (GWAS) of suicide attempts within a large, multi-ancestry cohort of U.S. veterans enrolled in the Million Veterans Program (MVP). Cases were defined as veterans with a documented history of suicide attempts in the electronic health record (EHR; N = 14,089) and controls were defined as veterans with no documented history of suicidal thoughts or behaviors in the EHR (N = 395,064). GWAS was performed separately in each ancestry group, controlling for sex, age and genetic substructure. Pan-ancestry risk loci were identified through meta-analysis and included two genome-wide significant loci on chromosomes 20 (p = 3.64 × 10-9) and 1 (p = 3.69 × 10-8). A strong pan-ancestry signal at the Dopamine Receptor D2 locus (p = 1.77 × 10-7) was also identified and subsequently replicated in a large, independent international civilian cohort (p = 7.97 × 10-4). Additionally, ancestry-specific genome-wide significant loci were also detected in African-Americans, European-Americans, Asian-Americans, and Hispanic-Americans. Pathway analyses suggested over-representation of many biological pathways with high clinical significance, including oxytocin signaling, glutamatergic synapse, cortisol synthesis and secretion, dopaminergic synapse, and circadian rhythm. These findings confirm that the genetic architecture underlying suicide attempt risk is complex and includes both pan-ancestry and ancestry-specific risk loci. Moreover, pathway analyses suggested many commonly impacted biological pathways that could inform development of improved therapeutics for suicide prevention.

Common variants in AGR1 genes contributed to the risk and traits of cirrhotic cardiomyopathy in Han Chinese population

Aim: This study aimed to determine the association between polymorphisms of the ARG1 gene and the risk and traits of cirrhotic cardiomyopathy (CCM). Methods: A total of 468 CCM and 1012 cirrhosis patients were enrolled, and 12 single-nucleotide polymorphisms (SNPs) in the ARG1 gene were genotyped. Differences in genotype, allele and haplotype frequencies of the SNPs between the CCM and cirrhosis groups were analyzed by chi-square test. Correlations of the genotypes of SNPs and representative traits of liver and heart function were performed using linear regression analysis. Results: SNPs rs2781666 and rs2781667 were associated with the risk of CCM in both dominant and additive inheritance models. The GG genotype frequency of rs2781666 and CC genotype frequency of rs2781667 were lower in the CCM group than in the cirrhosis group. The G-C haplotype frequency of the block consisting of rs2781666 and rs2781667 was higher and the T-T haplotype frequency was lower in CCM patients than in cirrhosis patients. SNP rs2781666 was associated with the alanine transaminase level, and rs2781667 was associated with the ARG1 level and left atrial diameter. Conclusion: SNPs rs2781666 and rs2781667 in the ARG1 gene were associated with susceptibility to and traits of CCM in the Han Chinese population.

TIMP2 genetic variation rs4789932 may associate with an increased risk of developing acne scarring based on a case-control study of Chinese Han population

BACKGROUND

Acne vulgaris is a common chronic inflammatory cutaneous disorder that has a higher prevalence in adolescents and young adults. Previous studies have indicated that both genetic and environmental factors contribute to its risk. The protein encoded by the TIMP2 gene is a natural inhibitor of matrix metalloproteinases (MMPs). Changes in TIMP2 expression are speculated to disrupt the TIMP/MMP balance and result in acne scarring.

AIMS

Our study aimed to comprehensively explore the potential genetic susceptibility of TIMP2 to acne scarring based on a case-control study.

PATIENTS AND METHODS

In total, 1060 patients with acne scarring (cases) and 2162 patients without acne scarring (controls) were enrolled in the present study. Seventeen tag single-nucleotide polymorphisms (SNPs) in the TIMP2 gene were selected for genotyping. Genetic association analyses were conducted at both the single marker and haplotypic levels. Single marker-based association analyses were performed in the genotypic model and allelic model. The distributions of clinical variables in different genotype groups of targeted SNPs in patients with acne scarring were also examined.

RESULTS

SNP rs4789932 was identified to be significantly associated with the risk of acne scarring in both the genotypic model (p = 0.001) and allelic model (p = 0.0002). The C allele of SNP rs4789932 was significantly associated with an increased risk of acne scarring (OR [95% CI] = 1.23 [1.10-1.37]). Significant differences were identified between the SNP rs4789932 genotypes and the clinical severity of acne scarring (p < 2.2 × 10^-16 ). The C allele of SNP rs4789932 was associated with severe clinical features of acne scarring.

CONCLUSIONS

A significant genetic marker of the promoter region in TIMP2 was identified to contribute to the risk of acne scarring in the Chinese Han population and was significantly associated with the clinical severity of acne scarring in patients.

Linking Diabetes Mellitus with Alzheimer's Disease: Bioinformatics Analysis for the Potential Pathways and Characteristic Genes

As the surging epidemics with significant disability, Alzheimer's disease (AD) and type II diabetes mellitus (T2DM) with microvascular complications are widely prevalent, sharing considerable similarities in putative pathomechanism. Despite a spurt of researches on the biology, knowledge about their interactive mechanisms is still rudimentary. Applying bioinformatics ways to explore the differentially co-expressed genes contributes to achieve our objectives to find new therapeutic targets. In this study, we firstly integrated gene expression omnibus datasets (GSE28146 and GSE43950) to identify differentially expressed genes. The enrichment analysis of pivotal genes, like gene ontology and pathway signaling proceeded subsequently. Besides, the related protein-protein interaction (PPI) network was then constructed. To further explain the inner connections, we ended up unearthing the biological significance of valuable targets. As a result, a set of 712, 630, 487, and 997 genes were differentially identified in T2DM with microvascular complications and AD at incipient, moderate, and severe, respectively. The enrichment analysis involving both diseases implicated the dominance of immune system, especially the noteworthy chemokine signaling. Multiple comparisons confirmed that CACNA2D3, NUMB, and IER3 were simultaneously participate in these two conditions, whose respective associations with neurological and endocrine diseases, and regulators including interacting chemicals, transcription factors, and miRNAs were analyzed. Bioinformatics analysis eventually concluded that immune-related biological functions and pathways closely link AD and T2DM with microvascular complications. Further exploration of the regulatory factors about CACNA2D3, NUMB, and IER3 in neuroendocrine field may provide us a promising direction to discover potential strategies for the comorbidity status.

Transcriptomics changes and the candidate pathway in human macrophages induced by different PM2.5 extracts

Ambient fine particulate matter (PM_2.5) is a worldwide environmental problem and is posing a serious threat to human health. Until now, the molecular toxicological mechanisms and the crucial toxic components of PM_2.5 remain to be clarified. This study investigated the whole transcriptomic changes in THP-1 derived macrophages treated with different types of PM_2.5 extracts using RNA sequencing technique. Bioinformatics analyses covering biological functions, signal pathways, protein networks and node genes were performed to explore the candidate pathways and critical genes, and to find the potential molecular mechanisms. Results of Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes pathway (KEGG), and protein-protein interaction (PPI) networks revealed that water extracts (WEs) of PM_2.5 obviously influenced genes and molecular pathways responded to oxidative stress and inflammation. Dichloromethane extracts (DEs) specifically affected genes and signal cascades related to cell cycle progress process. Furthermore, compared with WEs collected in heating season, non-heating season WEs induced much higher expression levels of Ca-associated genes (including phosphodiesterase 4B and cyclooxygenase-2), which may consequently result in more severe inflammatory responses. While, for DEs exposure, the heating season (DH) group showed extensive induction of deferentially expressed genes (DEGs) related to cell cycle pathway, which may be caused by the higher polycyclic aromatic hydrocarbons (PAHs) contents in DH samples than those from non-heating season. In conclusion, the oxidative stress and inflammation response are closely correlated with cellular responses in THP-1 derived macrophages induced by water soluble components of PM_2.5, and cell cycle dysregulation may play an important role in biological effects induced by organic components. The different transcriptomic changes induced by seasonal PM_2.5 extracts may partially depend on the contents of PAHs and metal ions, respectively.

The relationship between common variants in the DPEP1 gene and the susceptibility and clinical severity of osteoarthritis

AIM

Previous studies have provided evidence linking the DPEP1 gene to the risk of osteoarthritis (OA) in Europeans. In this study, we aimed to examine the relationship between DPEP1 gene and the susceptibility and clinical severity of OA in a Chinese Han population.

METHODS

This study comprised two independent samples. For the discovery stage, 1022 patients with knee OA and 1864 controls were recruited. Fourteen tag single nucleotide polymorphisms (SNPs) covering the DPEP1 gene were selected and genotyped. Associated SNPs in the discovery data set were subsequently genotyped in the replication data set consisting of 826 hip OA cases and 1662 controls. Both genotypic and allelic genetic associations were tested. The relationship of significant SNPs to the expression of DPEP1 and its neighboring genes was examined using the GTEx database.

RESULTS

A nonsynonymous SNP, rs1126464, was determined to be associated with the disease status of OA in both the discovery and replication stages (odds ratio [OR] 0.75, 95% confidence interval [95% CI] 0.68-0.82, P = 7.16 × 10^-11 ). This SNP was further characterized as being significantly related to a higher Kellgren-Lawrence grade in OA patients (OR 0.64, 95% CI 0.55-0.74, P = 2.53 × 10^-9 ). According to the GTEx data, SNP rs1126464 was significantly related to the gene expression of 15 genes in multiple types of human tissues.

CONCLUSION

We reported a common DNA variant in the DPEP1 gene that contributes to the risk of OA, providing additional evidence that the DPEP1 gene plays a significant role in the pathological mechanisms of OA.

Distinct effect of prenatal and postnatal brain expression across 20 brain disorders and anthropometric social traits: a systematic study of spatiotemporal modularity

Different spatiotemporal abnormalities have been implicated in different neuropsychiatric disorders and anthropometric social traits, yet an investigation in the temporal network modularity with brain tissue transcriptomics has been lacking. We developed a supervised network approach to investigate the genome-wide association study (GWAS) results in the spatial and temporal contexts and demonstrated it in 20 brain disorders and anthropometric social traits. BrainSpan transcriptome profiles were used to discover significant modules enriched with trait susceptibility genes in a developmental stage-stratified manner. We investigated whether, and in which developmental stages, GWAS-implicated genes are coordinately expressed in brain transcriptome. We identified significant network modules for each disorder and trait at different developmental stages, providing a systematic view of network modularity at specific developmental stages for a myriad of brain disorders and traits. Specifically, we observed a strong pattern of the fetal origin for most psychiatric disorders and traits [such as schizophrenia (SCZ), bipolar disorder, obsessive-compulsive disorder and neuroticism], whereas increased co-expression activities of genes were more strongly associated with neurological diseases [such as Alzheimer's disease (AD) and amyotrophic lateral sclerosis] and anthropometric traits (such as college completion, education and subjective well-being) in postnatal brains. Further analyses revealed enriched cell types and functional features that were supported and corroborated prior knowledge in specific brain disorders, such as clathrin-mediated endocytosis in AD, myelin sheath in multiple sclerosis and regulation of synaptic plasticity in both college completion and education. Our study provides a landscape view of the spatiotemporal features in a myriad of brain-related disorders and traits.

Na+ leak-current channel (NALCN) at the junction of motor and neuropsychiatric symptoms in Parkinson's disease

Parkinson's disease (PD) is a debilitating movement disorder often accompanied by neuropsychiatric symptoms that stem from the loss of dopaminergic function in the basal ganglia and altered neurotransmission more generally. Akinesia, postural instability, tremors and frozen gait constitute the major motor disturbances, whereas neuropsychiatric symptoms include altered circadian rhythms, disordered sleep, depression, psychosis and cognitive impairment. Evidence is emerging that the motor and neuropsychiatric symptoms may share etiologic factors. Calcium/ion channels (CACNA1C, NALCN), synaptic proteins (SYNJ1) and neuronal RNA-binding proteins (RBFOX1) are among the risk genes that are common to PD and various psychiatric disorders. The Na⁺ leak-current channel (NALCN) is the focus of this review because it has been implicated in dystonia, regulation of movement, cognitive impairment, sleep and circadian rhythms. It regulates the resting membrane potential in neurons, mediates pace-making activity, participates in synaptic vesicle recycling and is functionally co-localized to the endoplasmic reticulum (ER)-several of the major processes adversely affected in PD. Here, we summarize the literature on mechanisms and pathways that connect the motor and neuropsychiatric symptoms of PD with a focus on recurring relationships to the NALCN. It is hoped that the various connections outlined here will stimulate further discussion, suggest additional areas for exploration and ultimately inspire novel treatment strategies.

Common variants in LTBP3 gene contributed to the risk of hip osteoarthritis in Han Chinese population

Osteoarthritis (OA) is a common chronic joint disease affected by environmental and genetic factors. The LTBP3 gene may be involved in the occurrence and development of OA by regulating TGF-β activity and the TGF-β signaling pathway. A total of 2780 study subjects, including 884 hip OA cases and 1896 controls, were recruited. Nine tag single-nucleotide polymorphisms (SNPs) located within the LTBP3 gene region were selected for genotyping. Genetic association analyses were performed at both the genotypic and allelic levels. GTEx data were extracted to investigate the functional consequence of significant SNPs. SNP rs10896015 was significantly associated with the risk of hip OA at both the genotypic (P=0.0019) and allelic levels (P=0.0009). The A allele of this SNP was significantly associated with a decreased risk of HOA (OR [95%CI] = 0.79 [0.69–0.91]). This SNP was also significantly associated with the clinical severity of hip OA. SNP rs10896015 could affect the gene expression of 11 genes, including LTBP3, in multiple human tissues based on GTEx data. We obtained evidence for a genetic association between the LTBP3 gene and hip OA susceptibility and clinical severity based on Chinese Han populations. Our findings replicated the association signals reported by a recent genome-wide association study and deepen the basic understanding of osteoarthritis pathology.

Common variants in KCNK5 and FHL5 genes contributed to the susceptibility of migraine without aura in Han Chinese population

A recent genome-wide meta study suggested that rs67338227 in the FHL5 gene and rs10456100 in the KCNK5 gene are associated with migraine from 27 population-based cohorts excluding Chinese population. Given that migraine without aura (MO) is the most common subtype of migraine, our aim was to systematically investigate the relationship of common variants in FHL5 and KCNK5 genes with the susceptibility to MO and provide clues as to the nature of the mechanisms involved in the etiology of migraine. A total of 3306 subjects including 1042 patients with MO and 2264 controls were recruited for the discovery stage, and 2530 individuals including 842 patients with MO and 1688 controls for the replication stage. Twenty-two tag SNPs (7 from FHL5 and 15 from KCNK5) were selected for genotyping. Genetic associations were analyzed at both single-marker and haplotype levels. Potential functional consequences of the significant SNPs were analyzed using gene expression data obtained from the GTEx database. Two SNPs, rs10456100 (KCNK5, P = 9.01 × 10^-9) and rs7775721 (FHL5, P = 6.86 × 10^-13), were determined to be significantly associated with MO in the discovery sample and were then replicated in another sample. In the combined sample set, the T allele of both SNPs was significantly associated with the increased risk of MO. Significant eQTL signals were identified for both SNP rs10456100 and rs7775721. Our findings suggest that the T allele carriers of SNP rs10456100 and rs7775721 are at increased risk of migraine.

Evaluation of relationship between SPON1 gene and genetic susceptibility of postmenopausal osteoporosis

Purpose: Postmenopausal osteoporosis (PMOP) is one of systemic bone degenerative diseases characterised by decreased bone mineral density (BMD). Previous studies suggest that the SPON1 gene may be associated with BMD and play an important role in the occurrence and development of PMOP. In this study, we aimed to investigate the potential association between PMOP and the SPON1 gene.Methods: A total of 8062 postmenopausal women comprising 2684 primary PMOP patients, and 5378 healthy controls were recruited. Forty tag SNPs were selected for genotyping to evaluate the association of the SPON1 gene with PMOP and BMD. Genetic association and bioinformatics analyses were performed for PMOP.Results: SNP rs2697825 was identified to be significantly associated with the risk of PMOP at both allelic (T-statistics = -3.84, p = .0001) and genotypic levels (χ²=15.86, p = .0004). The G allele of SNP rs2697825 was significantly associated with a decreased risk of PMOP with an OR [95%] of 0.84 [0.77-0.92]. The G allele of SNP rs2697825 was associated with increased BMD at both the lumbar spine and femoral neck.Conclusions: Our results provide further evidence to support the important role for the SPON1 gene in the aetiology of PMOP, adding to the current understanding of the susceptibility to osteoporosis.

Gene Environment Interactions Between the COL9A1 Gene and Maternal Drinking of Alcohol Contribute to the Risk of Congenital Talipes Equinovarus

Background: Previous studies have indicated that both genetic and environmental factors contribute to the risk of congenital talipes equinovarus (CTEV). The COL9A1 gene encodes one of the three alpha chains of type IX collagen, which is a key collagen component of hyaline cartilage. Our study aimed to evaluate the effect of COL9A1 gene polymorphisms on susceptibility to CTEV in the Han Chinese population. Methods: A total of 2205 unrelated subjects comprising 692 CTEV patients and 1513 healthy controls were recruited. Demographic and characteristic information was collected, including maternal smoking and maternal drinking. Genetic association analyses and gene-environment interaction analyses were conducted based on the genotypic data of 36 tag single nucleotide polymorphisms (SNPs). Results: Although there was no association between genotyped SNPs and CTEV, a gene-environment interaction signal between SNP rs6455357 and maternal drinking was identified. Furthermore, significant heterogeneity was identified for this interaction signal when stratified by maternal drinking. For subjects with never maternal drinking, the A allele of SNP rs6455357 was significantly associated with a decreased risk of CTEV. In contrast, the A allele was associated with an increased risk of CTEV in the "occasional" and "often" groups. Conclusions: Our results indicate a combined effect of genetics and environmental factors on the etiology of CTEV. This study increases our understanding of the etiology of CETV and provides useful information for genetic counseling for at-risk families for the development of prevention programs and improved management.

Association of rs2862851 in TGFA Gene with Peripheral TGFA Levels and the Severity of Knee Osteoarthritis in the Han Chinese Population

Background: Osteoarthritis (OA) is a complex joint disorder characterized by sclerosis of subchondral bone. The knee is one of the most commonly affected joints. Given that the genetic mechanisms underlying knee OA remain elusive, our study aims were to first confirm the association of the TGFA gene alleles with the risk of knee OA and, second, to evaluate the relationship between peripheral TGFA concentrations and knee OA in an independent Han Chinese population. Materials and Methods: We performed a case-control study consisting of 392 knee OA patients and 808 unrelated healthy controls. Single-marker-based association analyses and haplotype-based analyses using 3 single nucleotide polymorphisms (SNPs) were performed to confirm the association of TGFA gene alleles with the risk of knee OA. Furthermore, we used enzyme-linked immunosorbent assay (ELISA) kits to detect the peripheral blood TGFA concentrations in patients and healthy controls and then evaluated the relationships between the TGFA alleles and genotypes with serum TGFA levels. Results: We replicated the genetic association of the rs2862851 T allele with the risk of knee OA (p = 1.68 × 10^-4, OR = 1.41). Moreover, we observed that the peripheral TGFA concentrations were higher in knee OA patients than in healthy controls (p = 8.15 × 10^-13). The peripheral TGFA concentrations were significantly different among the various rs2862851 genotypes for both cases (p = 4.16 × 10^-16) and controls (p = 7.24 × 10^-19). The individuals with the TT genotype in both cases and controls, had the highest peripheral TGFA concentrations. Moreover, with the increase in knee OA grade, peripheral TGFA concentration also increased (p = 1.36 × 10^-72). Conclusion: Our study confirmed the association of the TGFA gene with the risk of knee OA and identified a positive correlation between peripheral TGFA levels and the severity of knee OA in the Han Chinese population, providing clues for understanding the etiology of knee OA.

Evaluation of relationship between DNA methyltransferase 3 β gene and the risk of hip osteoarthritis: A case-control study based on a Han Chinese population

AIM

Osteoarthritis (OA) is a chronic degenerative joint disease. Early studies have indicated that genetic and environmental factors contribute to the risk of OA. However, the etiology of OA remains unknown. Our study aimed to evaluate the association of DNMT3B gene with the risk of hip OA in Han Chinese individuals.

METHODS

A total of 2070 subjects were recruited into the study, including 658 patients with hip OA and 1412 healthy controls. Twelve tag single nucleotide polymorphisms (SNPs) were selected and genotyped in our samples. Genetic associations between DNMT3B gene and the risk of hip OA were examined at both the single marker and haplotype levels. Cis-expression quantitative trait loci signals that achieve genome-wide significance of targeted SNPs from multiple types of human tissues were extracted from the GTEx database.

RESULTS

Significant signals were identified for SNP rs2424905 in 4 genetic models. The T allele was significantly associated with an increased risk of hip OA (odds ratio = 1.53; 95% CI = 1.28-1.83). The T allele was also significantly associated with higher Kellgren-Lawrence grade in the patients with hip OA (χ2  = 32.70, P = 1.37 × 10-6 ). Moreover, SNP rs2424905 was significantly associated with the gene expression level of multiple genes, including DNMT3B, C20orf203, COMMD7, EFCAB8, MAPRE1, and RP5-1085F17.3, from several types of human tissues.

CONCLUSION

Our results indicated that rs2424905 of DNMT3B gene contributed to the risk of hip OA and its clinical severity in a Han Chinese population. These findings suggested that rs2424905 of DNMT3B could be a promising genetic marker to assess susceptibility to hip OA in Han Chinese populations.

The effects of common variants in MDM2 and GNRH2 genes on the risk and survival of osteosarcoma in Han populations from Northwest China

Accumulating evidence has shown that both MDM2 and GNRH2 might be related to Osteosarcoma (OS) susceptibility. The study aimed to evaluate the effects of common variants in MDM2 and GNRH2 genes on the risk and survival of osteosarcoma in Han populations from Northwest China. In the study, we recruited 2292 subjects including 596 OS patients and 1696 healthy controls and genotyped 16 selected tag SNPs (6 from GNRH2 and 10 from MDM2). Genetic association analyses were performed at the genotypic and allelic levels. Survival curves were made for OS patients with different genotypes. Two SNPs, rs1690916 (MDM2, P = 0.0002) and rs3761243 (GNRH2, P = 0.0004), were identified to be significantly associated with OS risk. Moreover, SNP rs3761243 was strongly associated with pathological fracture (P = 2.61 × 10^–14), metastasis (P < 2.2 × 10^–16), and Enneking stage (P < 2.2 × 10^–16) in the OS group. Furthermore, survival curves based on different genotypes of SNP rs3761243 were found to be significantly different (P = 0.0003), suggesting increased risk with more copies of C alleles. Our results provide supportive evidence for genetic associations of MDM2 and GNRH2 genes with susceptibility to OS, and for the positive correlation of SNP rs3761243 in GNRH2 with the survival status of OS patients in Han populations from Northwest China.

Genome-Wide Search for SNP Interactions in GWAS Data: Algorithm, Feasibility, Replication Using Schizophrenia Datasets

In this study, we looked for potential gene-gene interaction in susceptibility to schizophrenia by an exhaustive searching for SNP-SNP interactions in 3 GWAS datasets (phs000021:phg000013, phs000021:phg000014, phs000167) using our recently published algorithm. The search space for SNP-SNP interaction was confined to 8 biologically plausible ways of interaction under dominant-dominant or recessive-recessive modes. First, we performed our search of all pair-wise combination of 729,454 SNPs after filtering by SNP genotype quality. All possible pairwise interactions of any 2 SNPs (5 × 10¹¹) were exhausted to search for significant interaction which was defined by p-value of chi-square tests. Nine out the top 10 interactions, protein coding genes were partnered with non-coding RNA (ncRNA) which suggested a new alternative insight into interaction biology other than the frequently sought-after protein-protein interaction. Therefore, we extended to look for replication among the top 10,000 interaction SNP pairs and high proportion of concurrent genes forming the interaction pairs were found. The results indicated that an enrichment of signals over noise was present in the top 10,000 interactions. Then, replications of SNP-SNP interaction were confirmed for 14 SNPs-pairs in both replication datasets. Biological insight was highlighted by a potential binding between FHIT (protein coding gene) and LINC00969 (lncRNA) which showed a replicable interaction between their SNPs. Both of them were reported to have expression in brain. Our study represented an early attempt of exhaustive interaction analysis of GWAS data which also yield replicated interaction and new insight into understanding of genetic interaction in schizophrenia.

SAP30BP gene is associated with the susceptibility of rotator cuff tear: a case-control study based on Han Chinese population

Background

Multiple studies have indicated that genetic components contribute significantly to the risk of rotator cuff tears. Previous studies have suggested that the SAP30BP gene may play an essential role in the development of rotator cuff tears. The aim of this study was to evaluate the potential association of the SAP30BP gene with the susceptibility to rotator cuff tears in a Han Chinese population.

Methods

A total of 394 patients with rotator cuff tears and 998 healthy controls were included in the study. Twelve tag single nucleotide polymorphisms (SNPs) located in the region of the SAP30BP gene were selected for genotyping. Genetic association analyses were performed using χ² tests for each SNP. Significant associations were searched in the GTEx database for their functional consequences.

Results

SNP rs820218 was significantly associated with rotator cuff tears (χ² = 9.49, P = 0.0021, OR [95% CI] = 0.67 [0.52–0.87]). In addition, SNP rs820218 was found to be significantly associated with the gene expression level of SAP30BP in whole blood (NES = 0.12, P = 1.00 × 10⁻⁶).

Conclusion

Our study has shown that the genetic polymorphism of SAP30BP contributes to the risk of rotator cuff tears in Chinese Han people. Individuals with the A allele for SNP rs820218 were less susceptible to developing rotator cuff tears.

Common Variants in the ARG1 Gene Contribute to the Risk of Dilated Cardiomyopathy in the Han Chinese Population

Background: Arginase I, encoded by the ARG1 gene, is an enzyme that catalyzes the conversion of arginine to ornithine in the urea cycle; mutations in this gene has recently been reported to be associated with dilated cardiomyopathy (DCM) in Pakistan. The present study aimed to investigate the relationship between ARG1 gene mutations and DCM in the Han Chinese population. Methods: A total of 488 DCM cases and 924 matched-healthy controls were recruited. All subjects were genotyped for 12 tag single nucleotide polymorphisms (SNPs) within the ARG1 gene. Genetic association studies, including SNP and haplotype analyses, were performed. Further analyses were conducted to examine the correlations between the associated SNPs and specific clinical characteristics. Results: Only the rs2781666 and rs2781667 loci in the ARG1 gene were found to be significantly associated with DCM compared to the healthy controls. The risk of DCM at both of these loci for T allele carriers was ∼1.42-fold higher than that for carriers of the alternative alleles. There were significant differences in end-diastolic interventricular septal diameter, end-diastolic left ventricular posterior wall diameter, left ventricular end-diastolic diameter, left ventricular end-systolic diameter, and left ventricular ejection fraction among the genotype distributions of both SNPs. Furthermore, we found that the T alleles at the rs2781666 and rs2781667 loci were significantly associated with DCM in gender subgroups and the subgroup of patients <58 years of age. The haplotype T-T (rs2781666-rs2781667) also showed a significant association with DCM. Conclusion: Our results support the hypothesis that alleles and haplotypes of the ARG1 gene are significantly involved in the etiology of DCM in the Han Chinese population, but further research is necessary to elucidate the mechanism governing this association.

Evaluation of genetic susceptibility of common variants in SOX9 in patients with congenital talipes equinovarus in the Han Chinese population

Background

Congenital talipes equinovarus (CTEV) is a common birth defect that causes severe deformities of one or both feet. Genetics have been proven to play a key role in the risk of CTEV. Our study aimed to evaluate the genetic susceptibility of common variants in the SOX9 gene to CTEV in a Han Chinese population.

Methods

In this study, we recruited 2,205 study participants, including 692 CTEV patients and 1513 healthy controls. A total of seven selected single-nucleotide polymorphisms (SNPs) within the SOX9 gene were genotyped, and environmental variables, including maternal smoking and alcoholic drinking habits, were assessed. In addition, bioinformatics analyses were performed to explore the potential biological functions of the associated SNPs.

Results

The SNP rs73354570 was identified to be significantly associated with the risk of CTEV (OR = 1.53, P = 2.11 × 10⁻⁵), and the C allele was associated with an increased risk of CTEV. A dose-dependent pattern could be observed in genotypic analyses. The OR for individuals with AC genotypes was 1.37 (95% CI 1.09–1.71), and the OR for individuals with CC homozygotes was 1.47 (95% CI 1.18–1.82). Further analyses identified that rs73354570 is located within a region of multiple binding proteins, including CEBPB and POLR2A, which suggested that this SNP was also part of genetic motifs that are found within several cell types.

Conclusion

Our results provide evidence supporting the important role of the SOX9 gene in the contribution to the risk of CTEV.

Neuronal α2δ proteins and brain disorders

α2δ proteins are membrane-anchored extracellular glycoproteins which are abundantly expressed in the brain and the peripheral nervous system. They serve as regulatory subunits of voltage-gated calcium channels and, particularly in nerve cells, regulate presynaptic and postsynaptic functions independently from their role as channel subunits. α2δ proteins are the targets of the widely prescribed anti-epileptic and anti-allodynic drugs gabapentin and pregabalin, particularly for the treatment of neuropathic pain conditions. Recently, the human genes (CACNA2D1-4) encoding for the four known α2δ proteins (isoforms α2δ-1 to α2δ-4) have been linked to a large variety of neurological and neuropsychiatric disorders including epilepsy, autism spectrum disorders, bipolar disorders, schizophrenia, and depressive disorders. Here, we provide an overview of the hitherto identified disease associations of all known α2δ genes, hypothesize on the pathophysiological mechanisms considering their known physiological roles, and discuss the most immanent future research questions. Elucidating their specific physiological and pathophysiological mechanisms may open the way for developing entirely novel therapeutic paradigms for treating brain disorders.

The Effect of Common Variants in SLC44A2 on the Contribution to the Risk of Deep Cein Thrombosis after Orthopedic Surgery

Aim: Deep vein thrombosis (DVT) is a common complication of orthopedic surgery. Multiple lines of evidence indicate that genetic factors play an important role in the development of DVT following orthopedic surgery (DVTFOS). Recent evidence suggested that the solute carrier family 44 member 2 (SLC44A) gene may contribute to the risk of DVT. In this study, we aimed to investigate the associations of SLC44A2 and DVTFOS in Chinese Han individuals.

Methods: In the study, 2,655 subjects, including 689 DVTFOS patients and 1,966 controls, were recruited. Eighteen SNPs were genotyped in the study. Genetic association analyses were performed at both the single marker and haplotype levels. Bioinformatics analyses were conducted to predict the functional consequences of significant SNPs.

Results: SNP rs2288904 of SLC44A2 was identified as being significantly associated with DVTFOS (P = 0.0003, OR [95%CI]= 1.28[1.12–1.46]). Allelic analyses showed that the G allele of this SNP significantly elevated the risks of DVTFOS, which was replicated in the genotypic association analyses. Moreover, a two-SNP haplotype, including rs2288904, was found to be strongly correlated with the risk of DVTFOS (P = 4.15 × 10⁻¹¹). Widespread effects in the expression quantitative trait loci were identified for rs2288904 in multiple tissues.

Conclusion: In summary, our results provide further supportive evidence of the association of SLC44A2 with the risk of DVTFOS, which also provide clues for understanding the important roles of the SLC44A2 gene in the pathogenesis of DVTFOS and in the development of preventive strategies.

Association Between Genetic Polymorphisms of CR2 Gene and the Risk of Steroid-Induced Osteonecrosis of the Femoral Head in the Chinese Han Male Population

Background: Multiple lines of evidence have suggested that genetic factors may contribute to steroid-induced osteonecrosis of the femoral head (SONFH). Complement receptor 2 (CR2), constituting a family of regulators of complement activation, has been recently reported to be associated with osteonecrosis of the femoral head (ONFH) in Koreans. The aim of this study was to evaluate the relationships between polymorphisms of the CR2 gene and susceptibility to SONFH in the male Han Chinese population. Materials and Methods: A total of 468 SONFH patients and 1224 healthy controls were recruited for this study. Ten tag single nucleotide polymorphisms (SNPs) located within the CR2 gene were genotyped. Genetic association analyses, including SNP and haplotypic analyses, were performed for the 10 SNPs. Furthermore, bioinformatic analyses were conducted to examine the functional consequences of SNPs shown to be significantly associated with SONFH. Results: An intronic SNP, rs311306, was identified to be significantly associated with the risk of SONFH (p = 0.0008, odds ratio = 1.44). Allelic analyses showed that the C allele of this SNP significantly elevated the risk of SONFH, which was replicated in genotypic association analyses. Moreover, a 3-SNP haplotype was significantly associated with SONFH (rs311306-rs17044576-rs3767933, p = 7.49 × 10^-8). Furthermore, bioinformatic analyses indicated limited functional consequences of SNP rs311306, but a complex interaction network was constructed for the protein encoded by the SLC44A2 gene and proteins encoded by the CD19, CD81, and C3 genes. Conclusion: Our findings shed new light on the link between the CR2 gene and SONFH in Han Chinese males, providing clues as to the nature of the mechanisms involved in the etiology of ONFH.

Evaluation of Common Variants in the AKNA Gene and Susceptibility to Knee Osteoarthritis Among the Han Chinese

Background: Osteoarthritis (OA) is a complex degenerative joint disease that is associated with both genetic and environmental factors. The AKNA gene, located at 9q32, has recently been identified as being associated with knee osteoarthritis (KOA) in the Mexican population. Our aim was to investigate the relationship of common variants in this gene with the risk of KOA in a large Han Chinese population. Methods: A total of 2,500 Han Chinese subjects were recruited, consisting of 824 KOA patients and 1,676 controls. Eight tag single nucleotide polymorphisms (SNPs) located within the ANKA gene were selected for genotyping. Single marker-based association analyses were conducted using multiple modes of inheritance, including genotypic, allelic, dominant, and recessive. Haplotype-based association analyses were also performed. Plink was utilized for genetic association analyses. In addition, we examined the GTEx database to test the expression quantitative loci effects of the significant SNPs within the AKNA gene. Results: Among these eight SNPs evaluated we identified one, rs10817595, as being significantly associated with the risk of KOA. Compared to the CC genotype at this locus, the odds ratio (95% confidence interval) for KOA with the AA genotype was 1.58 (1.23-2.01)-fold greater. A linkage disequilibrium block that included this SNP was also determined to be significantly associated with the risk of KOA (χ² = 25.08, p = 3.58 × 10^-6). In general, the minor allele A of SNP rs10817595 was associated with an increased risk of KOA. Conclusion: This study is the first to present evidence for a potential link between the risk of KOA and an AKNA gene polymorphism among persons with a Han Chinese ancestry. Future functional analyses based on animal models and sequencing-based population studies are needed to elucidate the biological plausibility and genetic architecture of AKNA for KOA susceptibility.

Relationship of COL9A1 and SOX9 Genes with Genetic Susceptibility of Postmenopausal Osteoporosis

As one of the most common types of osteoporosis, postmenopausal osteoporosis (PMOP) is caused by both genetic and environmental factors. Previous studies have indicated that SOX9 activity is tightly regulated to ensure normal bone mineral density (BMD) in the adult skeleton, and the COL9A1 promoter region can be transactivated by SOX9. In this study, we aimed to investigate the potential association between PMOP and the COL9A1 and SOX9 genes. A total of 10,443 postmenopausal women, including 2288 patients and 3557 controls in the discovery stage and 1566 patients and 3032 controls in the validation stage, were recruited. Forty-three tag SNPs (36 in COL9A1 and 7 in SOX9) were selected for genotyping to evaluate the association of the SOX9 gene with PMOP and BMD. Association and bioinformatics analyses were performed for PMOP. BMD and serum level of SOX9 were also utilized as quantitative phenotypes in further analyses. SNP rs73354570 of SOX9 was significantly associated with PMOP in both discovery stages (OR 1.24 [1.10-1.39], P = 3.56 × 10^-4, χ² = 12.75) and combined samples (OR 1.25 [1.15-1.37], P = 5.25 × 10^-7, χ² = 25.17). Further analyses showed that the SNP was also significantly associated with BMD and serum levels of the SOX9 protein. Our results provide further supportive evidence for the association of the SOX9 gene with PMOP and of the SOX9 gene with the variation of BMD in postmenopausal Han Chinese women. This study supports a role for SOX9 in the etiology of PMOP, adding to the current understanding of the susceptibility of osteoporosis.

Evaluation of Relationship Between Common Variants in FGF18 Gene and Knee Osteoarthritis Susceptibility

BACKGROUND AND AIMS

Osteoarthritis (OA) is the most common type of arthritis disease. Previous etiological studies indicated that both environmental and genetic factors play important roles in the occurrence and development of knee OA (KOA). In the present study, we aimed to investigate the association between the FGF18 gene and susceptibility to KOA in Han Chinese population.

METHODS

A total of 2,556 unrelated Han Chinese individuals, including 866 KOA patients and 1,688 healthy controls, were recruited. Nine tag SNPs located within the gene region of FGF18 were selected for genotyping. Logistic models were fitted for single marker-based association analyses. Age, gender and BMI were included in each model as covariates. To investigate the functional consequences of significant SNP, we extracted expression quantitative trait loci (eQTL) data from the GTEx database.

RESULTS

SNP rs3884606 was significantly associated with the risk of KOA (OR [95% CI] = 1.25 [1.11-1.41], p = 0.0002) after adjusting for age, gender and BMI. The G allele was significantly associated with an increased risk of KOA. No significant eQTL signals could be identified for SNP rs3884606 on FGF18.

CONCLUSION

In this study, we identified a genetic polymorphism in FGF18 that was significantly associated with the risk of KOA based on samples with Chinese Han ancestry. Our findings replicated the recent GWAS report and supported an association between KOA and FGF18.

Association of the CACNA2D2 gene with schizophrenia in Chinese Han population

Background

Schizophrenia (SCZ) is a severely complex psychiatric disorder in which ~80% can be explained by genetic factors. Single nucleotide polymorphisms (SNPs) in calcium channel genes are potential genetic risk factors for a spectrum of psychiatric disorders including SCZ. This study evaluated the association between SNPs in the voltage-gated calcium channel auxiliary subunit alpha2delta 2 gene (CACNA2D2) and SCZ in the Han Chinese population of Northeast China.

Methods

A total of 761 SCZ patients and 775 healthy controls were involved in this case-control study. Three SNPs (rs3806706, rs45536634 and rs12496815) of CACNA2D2 were genotyped by the MALDI-TOF-MS technology. Genotype distribution and allele frequency differences between cases and controls were tested by Chi-square (χ²) in males and females respectively using SPSS 24.0 software. Linkage disequilibrium and haplotype analyses were conducted using Haploview4.2. The false discovery rate correction was utilized to control for Type I error by R3.2.3.

Results

There was a significant difference in allele frequencies (χ² = 9.545, P_adj = 0.006) and genotype distributions (χ² = 9.275, P_adj = 0.006) of rs45536634 between female SCZ patients and female healthy controls after adjusting for multiple comparisons. Minor allele A (OR = 1.871, 95% CI [1.251–2.798]) and genotype GA + AA (OR = 1.931, 95% CI [1.259–2.963]) were associated with an increased risk of SCZ. Subjects with haplotype AG consisting of rs45536634 and rs12496815 alleles had a higher risk of SCZ (OR = 1.91, 95% CI [1.26–2.90]) compared those with other haplotypes.

Conclusions

This study provides evidence that CACNA2D2 polymorphisms may influence the susceptibility to SCZ in Han Chinese women.

Relationship of common variants in MPP7, TIMP2 and CASP8 genes with the risk of chronic achilles tendinopathy

Previous etiologic studies have indicated that both environmental and genetic factors play important roles in the occurrence and development of chronic Achilles tendinopathy (AT). A recent study documented the results of the largest genome-wide association study for chronic AT to date, indicating that MPP7, TIMP2 and CASP8 may be involved in the occurrence and development of chronic AT. In this study, we aimed to investigate whether MPP7, TIMP2 and CASP8 were associated with susceptibility to chronic AP in a Han Chinese population. A total of 3,680 study subjects comprised 1,288 chronic AT cases, and 2,392 healthy controls were recruited. Forty-four tag SNPs (7 from CASP8, 20 from MPP7, and 17 from TIMP2) were genotyped in the study. Genetic association analyses were performed at both single marker and haplotype levels. Functional consequences of significant SNPs were examined in the RegulomeDB and GTEx databases. Two SNPs, SNP rs1937810 (OR [95%CI] = 1.20 [1.09-1.32], χ2 = 13.50, P = 0.0002) in MPP7 and rs4789932 (OR [95%CI] = 1.24 [1.12-1.37], χ2 = 17.98, P = 2.23 × 10-5) in TIMP2, were significantly associated with chronic AT. Significant eQTL signals for SNP rs4789932 on TIMP2 were identified in human heart and artery tissues. Our results provide further supportive evidence for the association of the TIMP2 and MPP7 genes with chronic AT, which supports important roles for TIMP2 and MPP7 in the etiology of chronic AT, adding to the current understanding of the susceptibility of chronic AT.

Genetic Polymorphisms on 4q21.1 Contributed to the Risk of Hashimoto's Thyroiditis

Background: Hashimoto's thyroiditis (HT) is a common autoimmune disease characterized by lymphoid infiltration of the thyroid gland, including both T- and B-cells. Early studies have shown that HT is a complex disorder affected by both environmental and genetic factors. Recently, the single nucleotide polymorphism (SNP) rs2276886 associated with the CXCL9 gene was identified as associated with autoimmune thyroid disease susceptibility in Japanese populations. The aim of the present study was to validate this result for HT in a Chinese Han population. Methods: Study subjects, including 688 HT cases and 1456 healthy controls, were recruited, and 10 SNPs located within the CXCL9 gene were genotyped. Genetic association analyses were performed by fitting logistic models. Bioinformatics tools, including RegulomeDB and GTEx were utilized to investigate the functional consequences of the SNPs found to be significantly associated with HT. Results: SNP rs2276886 was identified as significantly associated with the risk of HT (odds ratio [OR] = 1.25, p = 0.0006). No significant expression quantitative trait loci (eQTL) signals could be identified for CXCL9. Significant eQTL signals were found for other genes, including ART3, CXCL10, CXCL11, NAAA, PPEF2, and SCARB2. This SNP physically maps to the CXCL9 gene region; however, further bioinformatic analyses indicated that this SNP might be associated with the gene NAAA. Conclusions: The rs2276886 SNP was found to be significantly associated with HT susceptibility. However, our findings suggest that this SNP which maps to the chromosomal region 4q21.1 likely effects the NAAA gene (as opposed to the CXCL9 gene), but still contributes to the susceptibility to HT in Han Chinese populations.

Genetic Associations between Voltage-Gated Calcium Channels and Psychiatric Disorders

Psychiatric disorders are mental, behavioral or emotional disorders. These conditions are prevalent, one in four adults suffer from any type of psychiatric disorders world-wide. It has always been observed that psychiatric disorders have a genetic component, however, new methods to sequence full genomes of large cohorts have identified with high precision genetic risk loci for these conditions. Psychiatric disorders include, but are not limited to, bipolar disorder, schizophrenia, autism spectrum disorder, anxiety disorders, major depressive disorder, and attention-deficit and hyperactivity disorder. Several risk loci for psychiatric disorders fall within genes that encode for voltage-gated calcium channels (CaVs). Calcium entering through CaVs is crucial for multiple neuronal processes. In this review, we will summarize recent findings that link CaVs and their auxiliary subunits to psychiatric disorders. First, we will provide a general overview of CaVs structure, classification, function, expression and pharmacology. Next, we will summarize tools to study risk loci associated with psychiatric disorders. We will examine functional studies of risk variations in CaV genes when available. Finally, we will review pharmacological evidence of the use of CaV modulators to treat psychiatric disorders. Our review will be of interest for those studying pathophysiological aspects of CaVs.

Evaluation of genetic susceptibility between systemic lupus erythematosus and GRB2 gene

Multiple lines of evidence have shown that systemic lupus erythematosus (SLE) is attributable to both genetic and environmental factors. The product of GRB2 is a key factor in the activation of B cells and has been reported to be significantly associated with SLE in European populations. In the study, we aimed to investigate the relationship between GRB2 and SLE. A total of 1,710 Han Chinese women comprising 567 SLE patients and 1,143 controls were recruited to genotype 20 selected tagging SNPs. We tested the potential association between 13 clinical variables of SLE and the significant polymorphisms related to SLE. The eQTL data were extracted from the GTEx database to examine the functional consequences of the targeted SNPs. A significant association signal was identified between rs36023980 and SLE in both genotypic and allelic analyses (OR = 0.61, P = 0.0003). Complement inhibition was shown to be significantly associated with the genotypes of SNP rs36023980 in SLE patients (P_genotype = 0.003). Further stratification analyses showed that the genetic association signal of SNP rs36023980 on SLE could only be identified in cases with complement inhibition. SNP rs36023980 was also identified to be significantly associated with the expression of GRB2 in whole blood and sun-exposed skin. In conclusion, our findings confirm the results from the previous GWAS and are the first to report the association of GRB2 with SLE in Han Chinese population.

Clinical phenotype and genetic risk factors for bipolar disorder with binge eating: an update

Introduction: Clinical and genetic study of psychiatric conditions has underscored the co-occurrence of complex phenotypes and the need to refine them. Bipolar Disorder (BD) and Binge Eating (BE) behavior are common psychiatric conditions that have high heritability and high co-occurrence, such that at least one quarter of BD patients have BE (BD + BE). Genetic studies of BD alone and of BE alone suggest complex polygenic risk models, with many genetic risk loci yet to be identified. Areas covered: We review studies of the epidemiology of BD+BE, its clinical features (cognitive traits, psychiatric comorbidity, and role of obesity), genomic studies (of BD, eating disorders (ED) defined by BE, and BD + BE), and therapeutic implications of BD + BE. Expert opinion: Subphenotyping of complex psychiatric disorders reduces heterogeneity and increases statistical power and effect size; thus, it enhances our capacity to find missing genetic (and other) risk factors. BD + BE has a severe clinical picture and genetic studies suggests a distinct genetic architecture. Differential therapeutic interventions may be needed for patients with BD + BE compared with BD patients without BE. Recognizing the BD + BE subphenotype is an example of moving towards more precise clinical and genetic entities.

Additional evidence supports association of common genetic variants in MMP3 and TIMP2 with increased risk of chronic Achilles tendinopathy susceptibility

OBJECTIVES

To systematically evaluate the effects of matrix metalloproteinase-3 (MMP3) and tissue inhibitor of metalloproteinase-2 (TIMP2) on chronic Achilles tendinopathy (AT) susceptibility. Chronic AT is one of the most prevalent and severe injuries in athletes. Early studies suggested that tendon extracellular matrix (ECM) may be involved in the pathogenesis of chronic AT. MMP3 is an important member of the MMP family and is important to ECM integrity. In addition, tissue inhibitor of metalloproteinase-2 (TIMP2) can indirectly limit the activity of MMP3 activity.

DESIGN

Case-control genetic association study.

METHODS

A total of 1084 chronic AT patients and 2188 controls with Chinese Han ancestry were recruited. Twenty-one SNPs, 4 mapped to MMP3 and 17 mapped to TIMP2, were selected and genotyped. Genetic association analyses and eQTL analyses were performed. In addition, we also examined the potential effects of epistasis using a case-only study design.

RESULTS

Two SNPs, rs679620 (OR=0.82, P=0.0006, MMP3) and rs4789932 (OR=1.2, P=0.0002, TIMP2) were identified to be significantly associated with chronic AT risk. No significant results were obtained from epistasis analyses. SNP rs4789932 was identified to be strongly associated with the gene expression level of TIMP2 in two types of human tissues: atrial appendage (P=0.0003) and tibial artery (P=0.0009).

CONCLUSIONS

We have identified genetic polymorphisms in MMP3 and TIMP2 to be significantly associated with chronic AT risk. Further eQTL analyses indicated that SNP rs4789932 of TIMP2 was related to the gene expression levels of TIMP2. These results suggest important roles for MMP3 and TIMP2 in the pathophysiology of chronic AT.

Evaluation of the Relationship Between Common Variants in the TLR-9 Gene and Hip Osteoarthritis Susceptibility

Objective: Hip osteoarthritis (HOA) is one of the most common types of osteoarthritis and affects nearly 10% of men and 18% of women who are >60 years of age worldwide. It has been demonstrated to be a genetic disease with a 50% heritability risk. Recently, the TLR-9 gene has been associated with knee OA in both Turkish and Chinese populations, but the relationship between the TLR-9 gene and HOA has not been evaluated. In this study, we aimed to evaluate the relationship between the common genetic variants in the TLR-9 gene and the predisposition of Han Chinese individuals to HOA. Methods: A total of 730 HOA patients and 1220 healthy controls were recruited in a hospital-based case-control study. Six common single nucleotide polymorphisms (SNPs) of the TLR-9 gene were selected for genotyping, and genetic association analyses were performed using both single-marker and haplotype-based methods. Results: The SNP rs187084 was found to be significantly associated with the risk of HOA after a Bonferroni correction (adjusted allelic p-values with age, gender, and body mass index [BMI] = 0.0008). The results indicated that the A allele of rs187084 is a risk allele for HOA and is likely to be a predisposing factor leading to an increased risk of HOA (adjusted odds ratio with age, gender, and BMI = 1.26, 95% confidence interval = 1.10-1.43). The results of the haplotype analyses confirmed a similar pattern to the SNP analyses. Conclusions: Our study provides strong evidence that variations in the TLR-9 gene are closely linked with genetic susceptibility to HOA in the Han Chinese population. This finding furthers the role of TLR-9 in the development and occurrence of OA in general.

Relationship Between Genetic Polymorphisms of the TNF Gene and Hallux Valgus Susceptibility

Background: Hallux valgus (HV) is a type of forefoot deformity affecting ∼23% of adults. Previous studies have shown that HV is highly heritable. Tumor necrosis factor (TNF) is an important proinflammatory cytokine involved in bone remodeling and plays essential roles in osteoarthritis and chronic inflammatory bone diseases, including HV. Methods: A total of 1,788 Chinese women comprising 637 HV subjects and 1,151 controls were recruited. Twelve single nucleotide polymorphisms (SNPs) located in TNF and its promoter regions were selected and genotyped. Genetic association analyses were performed to investigate potential susceptibility SNPs. Bioinformatic and expression quantitative trait loci (eQTL) analyses were conducted to examine the functional consequences of the SNPs identified as being significantly associated with HV. Results: SNP rs1800629, which is located at the 5' end of the promoter region of TNF, was identified as significantly associated with HV status in Chinese women (OR = 0.56, p = 2.12 × 10^-6). Bioinformatic analyses using RegulomeDB indicated that this SNP has important functional significance, but subsequent eQTL analyses did not identify a significant association between rs1800629 and TNF gene expression. In addition, 26 genes with cis-eQTL for rs1800629 were identified. Conclusions: This study identified a susceptibility SNP for HV located within the promoter region of the TNF gene. Bioinformatic and eQTL analyses linked this SNP to 26 genes but not to TNF. Functional studies are needed to more fully characterize the effects of this SNP.

Genetic susceptibility of common polymorphisms in NIN and SIGLEC5 to chronic periodontitis

Chronic periodontitis (CP) is a common oral disease characterized by the slow progression of alveolar attachment loss and bone destruction. Genetic components have been reported to play an important role in the onset and development of CP. In the present study, we aimed to replicate the association signals of NIN and SIGLEC5 identified in previous genome-wide association studies (GWASs) of samples from Chinese Han individuals. Association signals between clinical severity indicators of CP and relevant single nucleotide polymorphisms (SNPs) were also examined. A total of 3,160 study subjects, including 1,076 CP patients and 2,084 healthy controls, were recruited. A total of 32 SNPs, including 22 from NIN and 10 from SIGLEC5, were selected for genotyping. SNPs rs12883458 (OR = 1.45, P = 1.22 × 10-5, NIN) and rs4284742 (OR = 0.75, P = 1.69 × 10-5, SIGLEC5) were significantly associated with CP disease status. rs4284742 was significantly associated with all 3 clinical severity indicators, including bleeding on probing (BOP), probing depth (PD) and clinical attachment loss (CAL). According to evidence from bioinformatics analyses, both significant SNPs, rs12883458 and rs4284742, are likely surrogates of underlying variants with true effects. In summary, our findings provide direct evidence for the association of NIN and SIGLEC5 with CP susceptibility.

Relationship of common variants in Interleukin 33 gene with susceptibility and prognosis of osteosarcoma in Han Chinese population

Osteosarcoma (OS) is one of the most common malignant bone tumors. Many previous studies have indicated that OS is a complex disease and that its development may be affected by multiple genetic factors, which may contribute to its carcinogenesis. The aim of the present study was to evaluate the relationship of IL-33 with susceptibility and prognosis of OS in Han Chinese individuals. A total of 1,605 study subjects including 507 OS patients and 1,098 controls were recruited. Eighteen SNPs mapped to IL-33 were selected for genotyping. Genetic associations between selected SNPs and OS disease status were evaluated. Survival analyses, including Kaplan-Meier analysis and Cox model fitting for significant SNPs, were performed. The functional consequences of significant SNPs were analyzed using a publicly available database. SNP rs1048274 was identified to be significantly associated with OS disease status (OR=0.75, P=1.53×10-4). Compared to the GA and GG groups, OS patients with the AA genotype of rs1048274 had better survival rate. The hazard ratio of SNP rs1048274 (AA group compared to GG+GA group) was 0.35 (95% confidence interval of 0.25-0.5) following adjustment for several clinical variables. In conclusion, our results suggested that IL-33 may play a key role in the etiology of OS, indicating IL-33 as a potential genetic risk factor of the development and prognosis of OS.