Structural analysis of the locus containing the human C-reactive protein gene and its related pseudogene

Haplotype analysis on association between C-reactive protein gene and susceptibility to type 2 diabetes mellitus in Chinese Han population : CRP gene and type 2 diabetes mellitus

AIMS

We aimed to evaluate the impact of C-reactive protein (CRP) gene polymorphism, additional gene-gene interaction, and haplotypes on susceptibility to type 2 diabetes mellitus (T2DM).

METHODS

SNPstats online software ( https://www.snpstats.net/start.htm ) was employed to evaluate the association between CRP gene and T2DM risk. High-order interactions among SNPs was tested using generalized multifactor dimensionality reduction, and the testing balanced accuracy, training balanced accuracy and cross-validation consistency were calculated. The SHEsisPlus ( http://shesisplus.bio-x.cn/SHEsis.html ) online software was used for haplotype analysis.

RESULTS

A total of 730 T2DM patients and 765 controls were enrolled. The T allele of rs1205 is associated with increased susceptibility to T2DM, OR (95% CI) were 1.51 (1.13-2.01), 1.44 (1.10-1.89) and 1.25 (1.01-1.54) for codominant, dominant and over-dominant models, respectively. We also found that minor allele of rs2794521 is associated with decreased susceptibility to T2DM under codominant and recessive models, OR (95%CI) were 0.38 (0.18-0.79) and 0.37 (0.16-0.80) for codominant and recessive models, respectively. No significant gene-gene interaction existed among CRP gene SNPs, all interaction p- values were more than 0.05. Haplotype analyses suggested the CGCA haplotype containing rs1205-C, rs1130864-G, rs2794521- C and rs3093059- A allele was associated with decreased risk of T2DM, OR (95% CI) = 0.83 (0.68-0.98), P = 0.047.

CONCLUSIONS

Minor allele of rs1205 was associated with increased T2DM risk. Minor allele of rs2794521 and the CGCA haplotype were associated with decreased T2DM risk.

Genome-wide Association Analysis of Proinflammatory Cytokines and Gene-lifestyle Interaction for Invasive Breast Cancer Risk: The WHI dbGaP Study

Immune-related etiologic pathways to influence invasive breast cancer risk may interact with lifestyle factors, but the interrelated molecular genetic pathways are incompletely characterized. We used data from the Women's Health Initiative Database for Genotypes and Phenotypes Study including 16,088 postmenopausal women, a population highly susceptible to inflammation, obesity, and increased risk for breast cancer. With 21,784,812 common autosomal single-nucleotide polymorphisms (SNP), we conducted a genome-wide association (GWA) gene-environment interaction (G × E) analysis in six independent GWA Studies for proinflammatory cytokines [IL6 and C-reactive protein (CRP)] and their gene-lifestyle interactions. Subsequently, we tested for the association of the GWA SNPs with breast cancer risk. In women overall and stratified by obesity status (body mass index, waist circumference, and waist-to-hip ratio) and obesity-related lifestyle factors (exercise and high-fat diet), 88 GWA SNPs in 10 loci were associated with proinflammatory cytokines: 3 associated with IL6 (1 index SNP in MAPK1 and 1 independent SNP in DEC1); 85 with CRP (3 index SNPs in CRPP1, CRP, RP11-419N10.5, HNF1A-AS1, HNF1A, and C1q2orf43; and two independent SNPs in APOE and APOC1). Of those, 27 in HNF1A-AS1, HNF1A, and C1q2orf43 displayed significantly increased risk for breast cancer. We found a number of novel top markers for CRP and IL6, which interacted with obesity factors. A substantial proportion of those SNPs' susceptibility influenced breast cancer risk. Our findings may contribute to better understanding of genetic associations between pro-inflammation and cancer and suggest intervention strategies for women who carry the risk genotypes, reducing breast cancer risk. PREVENTION RELEVANCE: The top GWA-SNPs associated with pro-inflammatory biomarkers have implications for breast carcinogenesis by interacting with obesity factors. Our findings may suggest interventions for women who carry the inflammatory-risk genotypes to reduce breast cancer risk.

Association between C-reactive protein gene variant and treatment efficacy of etanercept in ankylosing spondylitis patients receiving hip arthroplasty

BACKGROUND

C-reactive protein (CRP) level is one of the most widely used parameters to assess ankylosing spondylitis (AS), since CRP is associated with poor radiographic progression of AS patients. Recent studies have investigated the association between CRP gene variants and AS risk, but with conflicting findings.

MATERIAL AND METHODS

We enrolled 232 AS cases and 314 controls in this case-control study. Next, we assessed the association of CRP gene rs3091244 polymorphism with the efficacy of etanercept for AS. Genotyping was done using a custom-by-design 48-Plex SNP scanTM Kit.

RESULTS

CRP gene rs3091244 polymorphism was associated with an increased risk of AS in this Chinese population. Clinical indicators of AS patients including morning stiffness time, Bath AS function index (BASFI), Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), Visual Analogue Scale (VAS), erythrocyte sedimentation rate (ESR), and CRP were significantly decreased after 12 weeks of etanercept treatment. Furthermore, AA genotype carriers showed higher values of VAS, BASDAI, BASFI, and CRP before etanercept treatment. AA genotype or A allele of rs3091244 polymorphism was associated with Ankylosing Spondylitis Assessment Study group response criteria 20 scores (ASAS20) and Assessment in SpondyloArthritis international Society 40 response (ASAS40) improvement. In addition, AA genotype carriers showed significantly higher CRP levels compared with genotype GG carriers (16.3 vs 8.8 mg/L).

CONCLUSION

CRP gene rs3091244 polymorphism is associated with an increased risk of AS. Additionally, rs3091244 polymorphism could serve as a biomarker for good response to etanercept treatment in AS.

The relationship between CRP gene polymorphism (rs2794521, rs3091244), ASDAS-CRP and ASDAS-ESR in ankylosing spondylitis

Background: We aimed to investigate the haplotypes and alleles of two variants (rs2794521 and rs3091244) in AS patients and to examine their relationship with ASDAS-CRP and ASDAS-ESR values.Methods: We evaluated 160 AS patients diagnosed according to the ASAS criteria. ASDAS-CRP and ASDAS-ESR values were calculated. ESR and CRP were examined. The restriction fragment length polymorphism (RFLP) method was used for detecting the rs2794521 and rs3091244 regions on the CRP gene.Results: As a result of the evaluation of rs2794521 gene polymorphism using PCR, TT, TC and CC genotypes were observed in 90, 81 and 9 individuals, respectively. As a result of the evaluation of rs3091244 gene polymorphism, CC, AC and TT genotypes were observed in 104, 51 and 5 individuals, respectively. T allele and C allele were found in rs2794521 gene by 75% and 25%, respectively. In addition, T allele, C allele and A allele were found in rs3091244 gene by 80%, 17% and 3%, respectively. With the help of regression equation, ASDAS-CRP level was 0.34 units higher in cases with rs3091244 C allele than cases without rs3091244 C alleles.Conclusion: CRP rs3091244 C allele may be associated with the increased relative risk for ASDAS-CRP.

Selecting instruments for Mendelian randomization in the wake of genome-wide association studies

Mendelian randomization (MR) studies typically assess the pathogenic relevance of environmental exposures or disease biomarkers, using genetic variants that instrument these exposures. The approach is gaining popularity-our systematic review reveals a greater than 10-fold increase in MR studies published between 2004 and 2015. When the MR paradigm was first proposed, few biomarker- or exposure-related genetic variants were known, most having been identified by candidate gene studies. However, genome-wide association studies (GWAS) are now providing a rich source of potential instruments for MR analysis. Many early reviews covering the concept, applications and analytical aspects of the MR technique preceded the surge in GWAS, and thus the question of how best to select instruments for MR studies from the now extensive pool of available variants has received insufficient attention. Here we focus on the most common category of MR studies-those concerning disease biomarkers. We consider how the selection of instruments for MR analysis from GWAS requires consideration of: the assumptions underlying the MR approach; the biology of the biomarker; the genome-wide distribution, frequency and effect size of biomarker-associated variants (the genetic architecture); and the specificity of the genetic associations. Based on this, we develop guidance that may help investigators to plan and readers interpret MR studies.

The relationship between C-reactive protein rs3091244 polymorphism and ankylosing spondylitis

AIMS

Previous studies have shown that C-reactive protein (CRP) gene polymorphism can be related to inflammatory changes. The present study aimed to examine the association between CRP gene polymorphism and clinical and laboratory findings in ankylosing spondylitis (AS) patients.

MATERIALS AND METHODS

A total of 80 patients, 40 with AS and 40 controls, were included in the study. Diagnosis of AS was made according to Assessment in AS International Working Group criteria. Bath Ankylosing Spondylitis Disease Activity Index, Bath Ankylosing Spondylitis Functional Index, Bath Ankylosing Spondylitis Metrology Index and Bath Ankylosing Spondylitis Radiology Index scores were evaluated. CRP gene C, A and T alleles were evaluated and were determined using the analysis of melting curves after real time polymerase chain reaction. The odds ratios were calculated for all alleles and haploids of the CRP gene. We investigated the relationship between the CRP polymorphism and clinical and laboratory findings.

RESULTS

A, C, T allele frequencies in the control group were 15%, 57.5% and 27.5%. The allele frequencies in the AS group were 38%, 68.8% and 26.2%. While C and T allele frequencies were shown to be similar in the two groups, A allele frequency was higher in the AS group compared to the control group. The CC wild allele was 42.5% in the control group and 47.5% in the AS group (P = 1.0). Odds ratios for the C allele were 1.6, for the CC haploid 1.2 and for the CT haploid 3.7. Chest expansion and finger-to-ground distance was better in the CRP gene polymorphism group compared to the no polymorphism group.

CONCLUSION

The presence of the CRP gene CC wild haploid and C allele in patients may indicate an increased risk for AS.

Proinflammatory cytokines in CRP baseline regulation

Low-grade inflammation, a minor elevation in the baseline concentration of inflammatory markers such as C-reactive protein (CRP), is nowadays recognized as an important underlying condition in many common diseases. Concentrations of CRP under 10 mg/1 are called low-grade inflammation and values above that are considered as clinically significant inflammatory states. Epidemiological studies have revealed demographic and socioeconomic factors that associate with CRP concentration; these include age, sex, birth weight, ethnicity, socioeconomic status, body mass index (BMI), fiber consumption, alcohol intake, and dietary fatty acids. At the molecular level, production of CRP is induced by proinflammatory cytokines IL-1, IL-6, and IL-17 in the liver, although extra hepatic production most likely contributes to systemic concentrations. The cytokines are produced in response to, for example, steroid hormones, thrombin, C5a, bradykinin, other cytokines, UV-light, neuropeptides and bacterial components, such as lipopolysaccharide. Cytokines exert their biological effects on CRP by signaling through their receptors on hepatic cells and activating different kinases and phosphatases leading to translocation of various transcription factors on CRP gene promoter and production of CRP protein. Genetic polymorphisms in the interleukin genes as well as in CRP gene have been associated with minor elevation in CRP. As minor elevation in CRP is associated with both inflammatory and noninflammatory conditions, it should be noticed that the elevation might just reflect distressed or injured cells homeostasis maintenance in everyday life, rather than inflammation with classical symptoms of redness, swelling, heat, and pain.

C-Reactive Protein Gene Polymorphisms, C-Reactive Protein Blood Levels, and Cardiovascular Disease Risk

C-reactive protein (CRP), a blood marker of inflammation and a hallmark of the acute-phase response, has been shown to be a powerful and specific predictor of cardiovascular event risk in populations of otherwise healthy persons. Here we review what is known about CRP gene polymorphisms, discuss how these might affect the epidemiology of CRP and our understanding of CRP's contribution to cardiovascular disease, and examine their potential clinical usefulness. Evidence shows that certain subtle variations in the CRP gene sequence, mostly single nucleotide polymorphisms, predictably and strongly influence the blood level of CRP. Some of these variations are associated with clinical correlates of cardiovascular disease. If future studies can establish with certainty that CRP influences cardiovascular biology, then CRP gene profiling could have clinical utility.

Fine mapping of the human pentraxin gene region on chromosome 1q23

The 1q21 to 25 region of human chromosome 1 contains genes which encode proteins with immune- and inflammation-associated functions. These include the pentraxin genes, for C-reactive protein (CRP), serum amyloid P (SAP) protein (APCS),a nd a CRP pseudogene (CRPP1). The region of chromosome 1 containing this cluster is syntenic with distal mouse chromosome 1. We constructed an approximately 1.4 megabase yeast artificial chromosome (YAC) contig with the pentraxin genes at its core. This four-YAC contig includes other genes with immune functions including the FCER1A gene, which encodes the alpha-subunit of the IgE high-affinity Fc receptor and the IFI-16 gene, an interferon-gamma-induced gene. In addition, it contains the histone H3F2 and H4F2 genes and the gene for erythroid alpha-spectrin (SPTA1). The gene order is cen.-SPTA1-H4F2-H3F2-IFI-16-CRP-CRPP1-APCS -FCER1A- tel. The contig thus consists of a cluster of genes whose products either have immunological importance, bind DNA, or both.

Comparison of sequence of cDNA clone with other genomic and cDNA sequences for human C-reactive protein

A clone for C-reactive protein (CRP) has been isolated from a human liver cDNA library; this clone harbors a plasmid, pC81, which has an insert of 1631 bp. When compared to genomic and cDNA sequences published to date now, pC81 has revealed homologies and differences that might help to clarify the structure of this gene and the presence of allelic variants in man.