SHEsis,a powerful software platform for analyses of linkage disequilibrium,haplotype construction,and genetic association at polymorphism loci

In multiloci-based genetic association studies of complex diseases, a powerful and high efficient tool for analyses oflinkage disequilibrium (LD) between markers, haplotype distributions and many chi-square/p values with a large numberof samples has been sought for long. In order to achieve the goal of obtaining meaningful results directly from raw data,we developed a robust and user-friendly software platform with a series of tools for analysis in association study withhigh efficiency. The platform has been well evaluated by several sets of real data.

No evidence for a genetic association between female mating preference and male secondary sexual trait in a Lake Victoria cichlid fish

Sexual selection by female mating preference for male nuptial coloration has been suggested as a driving force in the rapid speciation of Lake Victoria cichlid fish. This process could have been facilitated or accelerated by genetic associations between female preference loci and male coloration loci. Preferences, as well as coloration, are heritable traits and are probably determined by more than one gene. However, little is known about potential genetic associations between these traits. In turbid water, we found a population that is variable in male nuptial coloration from blue to yellow to red. Males at the extreme ends of the phenotype distribution resemble a reproductively isolated species pair in clear water that has diverged into one species with blue-grey males and one species with bright red males. Females of the turbid water population vary in mating preference coinciding with the male phenotype distribution. For the current study, these females were mated to blue males. We measured the coloration of the sires and male offspring. Parents-offspring regression showed that the sires did not affect male offspring coloration, which confirms earlier findings that the blue species breeds true. In contrast, male offspring coloration was determined by the identity of the dams, which suggests that there is heritable variation in male color genes between females. However, we found that mating preferences of the dams were not correlated with male offspring coloration. Thus, there is no evidence for strong genetic linkage between mating preference and the preferred trait in this population [Current Zoology 56 （1）： 57-64 2010].

Genetic associations with adverse events from anti-tumor necrosis factor therapy in inflammatory bowel disease patients

AIM To study the type and frequency of adverse events associated with anti-tumor necrosis factor(TNF)therapy and evaluate for any serologic and genetic associations.METHODS This study was a retrospective review of patients attending the inflammatory bowel disease(IBD) centers at Cedars-Sinai IBD Center from 2005-2016. Adverse events were identified via chart review. IBD serologies were measured by ELISA. DNA samples were genotyped at Cedars-Sinai using Illumina Infinium Immunochipv1 array per manufacturer's protocol. SNPs underwent methodological review and were evaluated using several SNP statistic parameters to ensure optimal allele-calling. Standard and rigorous QC criteria were applied to the genetic data, which was generated using immunochip. Genetic association was assessed by logistic regression after correcting for population structure.RESULTS Altogether we identified 1258 IBD subjects exposed to anti-TNF agents in whom Immunochip data were available. 269/1258 patients(21%) were found to have adverse events to an anti-TNF-α agent that required the therapy to be discontinued. 25% of women compared to 17% of men experienced an adverse event. All adverse events resolved after discontinuing the antiTNF agent. In total: n = 66(5%) infusion reactions; n = 49(4%) allergic/serum sickness reactions; n = 19(1.5%) lupus-like reactions, n = 52(4%) rash, n = 18(1.4%) infections. In Crohn's disease, Ig A ASCA(P = 0.04) and Ig G-ASCA(P = 0.02) levels were also lower in patients with any adverse events, and anti-I2 level in ulcerative colitis was significantly associated with infusion reactions(P = 0.008). The logistic regression/human annotation and network analyses performed on the Immunochip data implicated the following five signaling pathways: JAK-STAT(Janus Kinase-signal transducer and activator of transcription), measles, IBD, cytokine-cytokine receptor interaction, and toxoplasmosis for any adverse event. CONCLUSION Our study shows 1 in 5 IBD patients experience an adverse event to anti-TNF therapy with novel serologic, genetic, and pathways associations.

SHEsis,a powerful software platform for analyses of linkage disequi-librium,haplotype construction,and genetic association at polymor-phism loci

The authors want to changed the web link of the software platform in this Briefing.Page 97,section 'INTRODUCTION',the web link of SHEsis is changed from http://www.nhgg.org/analysis tohttp://analysis.bio-x.

Genetic association of rs7754840 and rs7756992 polymorphisms in the CDKAL1 gene and gestational diabetes mellitus in selected Filipino pregnant women

Objective:To investigate the possible association between rs7754840 and rs7756992 polymorphisms of CDKAL1 gene and susceptibility to gestational diabetes mellitus(GDM)in a Filipino pregnant population.Methods:A total of 101 patients with GDM and 99 women without GDM were included.Two CDKAL1 gene single nucleotide polymorphisms(SNPs),namely rs7754840 and rs7756992,were genotyped by using TaqMan allelic discrimination assays.Mann-Whitney U test,median and interquartile range were used to describe physical and biochemical characteristics.The differences in the genotype and allele distribution of the target genetic variants among the two groups of participants were assessed by using Chi-square test.Conformity to Hardy-Weinberg equilibrium was tested prior to conducting further analysis.Multiple logistic regression model was used to investigate the effects of the genotype models on GDM development.Results:There was no observed correlation between the genotypes of the rs7754840 SNP and oral glucose tolerance test parameters.Consequently,there was no significant association between genetic models of the rs7754840 SNP and GDM risk(additive OR 1.43,95%CI 0.82-2.50,P=0.21;dominant OR 1.21,95%CI 0.57-2.59,P=0.62;recessive OR 1.63,95%CI 0.86-3.09,P=0.13).Conclusions:The results of this study suggest no association between CDKAL1 gene variant rs7754840 and GDM development in Filipino pregnant women.Further studies with a larger population should be performed to validate our findings.

Genetic association of Parkinson's disease

Totally three articles regarding associations of Nurrl gene mutations, LRRK2 gene polymorphism sites $1647T and R1398H, and polymorphism of PARK2 gene mutations with Han Chinese patients with Parkinson＇s disease were published in Neural Regeneration Research. We hope that our readers find these papers useful to their research.

No association between cyclooxygenase-2 and uridine diphosphate glucuronosyltransferase 1A6 genetic polymorphisms and colon cancer risk

AIM：To investigate the association of variations in the cyclooxygenase-2 （COX2） and uridine diphosphate glucuronosyltransferase 1A6 （UGTIA6） genes and non-steroidal anti-inflammatory drugs （NSAIDs） use with risk of colon cancer.METHODS： NSAIDs, which are known to reduce the risk of colon cancer, act directly on COX2 and reduce its activity. Epidemiological studies have associated variations in the COX2 gene with colon cancer risk, but others were unable to replicate this finding. Similarly,enzymes in the UGT1A6 gene have been demonstrated to modify the therapeutic effect of NSAIDs on colon adenomas. Polymorphisms in the UGTIA6 gene have been statistically shown to interact with NSAID intake to influence risk of developing colon adenomas, but not colon cancer. Here we examined the association of tagging single nucleotide polymorphisms （SNPs） in the COX2 and UGTIA6 genes, and their interaction with NSAID consumption, on risk of colon cancer in a population of 422 colon cancer cases and 481 population controls.RESULTS： No SNP in either gene was individually statistically significantly associated with colon cancer, nor did they statistically significantly change the protective effect of NSAID consumption in our sample. Like others, we were unable to replicate the association of variants in the COX2 gene with colon cancer risk （P 〉 0.05）,and we did not observe that these variants modify the protective effect of NSAIDs （P 〉 0.05）. We were able to confirm the lack of association of variants in UGT1A6 with colon cancer risk, although further studies will have to be conducted to confirm the association of these variants with colon adenomas.CONCLUSION： Our study does not support a role of COX2 and UGTIA6 genetic variations in the development of colon cancer.

Finding susceptible and protective interaction patterns in large-scale genetic association study

Interaction detection in large-scale genetic asso- ciation studies has attracted intensive research interest, since many diseases have complex traits. Various approaches have been developed for finding significant genetic interactions. In this article, we propose a novel framework SRMiner to detect interacting susceptible and protective genotype patterns. SR- Miner can discover not only probable combination of single nucleotide polymorphisms （SNPs） causing diseases but also the corresponding SNPs suppressing their pathogenic func- tions, which provides a better prospective to uncover the un- derlying relevance between genetic variants and complex dis- eases. We have performed extensive experiments on several real WeUcome Trust Case Control Consortium （WTCCC） datasets. We use the pathway-based and the protein-protein interaction （PPI） network-based evaluation methods to verify the discovered patterns. The results show that SRMiner successfully identifies many disease-related genes verified by the existing work. Furthermore, SRMiner can also infer some uncomfirmed but highly possible disease-related genes.

Genetic Variations and Nonalcoholic Fatty Liver Disease:Field Synopsis,Systematic Meta-Analysis,and Epidemiological Evidence

Objective To systematically summarize the published literature on the genetic variants associated with nonalcoholic fatty liver disease(NAFLD).Methods Literature from Web of Science,PubMed,and Embase between January 1980 and September 2022 was systematically searched.Meta-analyses of the genetic variants were conducted using at least five data sources.The epidemiologic credibility of the significant associations was graded using the Venice criteria.Results Based on literature screening,399 eligible studies were included,comprising 381 candidate gene association,16 genome-wide association,and 2 whole-exome sequencing studies.We identified 465 genetic variants in 173 genes in candidate gene association studies,and 25 genetic variants in 17 genes were included in the meta-analysis.The meta-analysis identified 11 variants in 10 genes that were significantly associated with NAFLD,with cumulative epidemiological evidence of an association graded as strong for two variants in two genes(HFE,TNF),moderate for four variants in three genes(TM6SF2,GCKR,and ADIPOQ),and weak for five variants in five genes(MBOAT7,PEMT,PNPLA3,LEPR,and MTHFR).Conclusion This study identified six variants in five genes that had moderate to strong evidence of an association with NAFLD,which may help understand the genetic architecture of NAFLD risk.

Lack of Association between Genetic Polymorphisms Affecting Autonomic Activity and Coronary Artery Spasm

Coronary artery spasm （CAS） is one of the leading pathological causes of a wide spectrum of ischemic heart diseases, ranging from variant angina pectoris to acute myocardial infarction and even sudden cardiac death[1]. Furthermore, Pierron et al. concluded that CAS of angiographically normal or sub-normal arteries is responsible for death or myocardial infarction in 11.6% of all cases. Oddly, the incidence of CAS is remarkably higher in Asians than in Caucasians[3], suggesting genetic involvement In its pathogenesis.

Genetic epidemiology of primary sclerosing cholangitis

The aetiology of primary sclerosing cholangitis (PSC) is not known. A more than 80-fold increased risk of PSC among first-degree relatives emphasizes the importance of genetic factors. Genetic associations within the human leukocyte antigen (HLA) complex on chromosome 6p21 were detected in PSC 25 years ago. Subsequent studies have substantiated beyond doubt that one or more genetic variants located within this genetic region are important. The true identities of these variants,however,remain to be identified. Several candidate genes at other chromosomal loci have also been investigated. However,according to strict criteria for what may be denominated a susceptibility gene in complex diseases,no such gene exists for PSC today. This review summarises present knowledge on the genetic susceptibility to PSC,as well as genetic associations with disease progression and clinical subsets of particular interest (inflammatory bowel disease and cholangiocarcinoma).

Pooled genetic analysis in ultrasound measured non-alcoholic fatty liver disease in Indian subjects:A pilot study

AIM: To investigate genetic susceptibility in Indian subjects with non-alcoholic fatty liver disease(NAFLD) by performing a pooled genetic study.METHODS: Study subjects(n = 306) were recruited and categorized into NAFLD and control groups based on ultrasound findings of fatty infiltration. Of the 306 individuals, 156 individuals had fatty infiltration and thus comprised the NAFLD group. One hundred and fifty(n = 150) individuals were normal, without fatty infiltration of the liver, comprising the control group. Blood samples, demographic and anthropometric data from the individuals were collected after obtaining informed consent. Anthropometric data, blood glucose, lipids and liver function tests were estimated using standard methods. Genome wide association stud-ies done to date on NAFLD were identified, 19 single nucleotide polymorphisms(SNPs) were selected from these studies that were reported to be significantly associated with NAFLD and genotyping was performed on the Sequenom platform. Student's t test for continuous variables and χ2 test was applied to variant carriers from both groups. Required corrections were applied as multiple testing was done.RESULTS The mean age of the control group was 39.78 ± 10.83 and the NAFLD group was 36.63 ± 8.20 years. The waist circumference of males and females in the control and NAFLD groups were 80.13 ± 10.35; 81.77 ± 13.65 and 94.09 ± 10.53; 92.53 ± 8.27 respectively. The mean triglyceride and alanine transaminase(ALT) levels in the control and NAFLD groups were 135.18 ± 7.77; 25.39 ± 14.73 and 184.40 ± 84.31; 110.20 ± 67.05 respectively. When χ2 test was applied to the number of individuals carrying the variant risk alleles between the control and NAFLD group, a significant association was seen between rs738409 of the patatin-like phospholipase domain containing 3(PNPLA3) gene(P = 0.001), rs2073080 of the PARVB gene(P = 0.02), rs2143571 of SAMM50 gene(P = 0.05) and rs6487679 of the pregnancy zone protein(PZP) gene(P = 0.01) with the disease. Variant single nucleotide polymorphisms(SNPs) in NCAN and PNPLA3 gene were associated with higher levels of ALT, whereas variant SNPs in APOC3, PNPLA3, EFCAB4 B and COL13A1 were associated with high triglyceride levels. Apart from the above associations, rs2073080, rs343062 and rs6591182 were significantly associated with high BMI; rs2854117 and rs738409 with high triglyceride levels; and rs2073080, rs2143571, rs2228603, rs6487679 and rs738409 with high ALT levels.CONCLUSION: Pooled genetic analysis revealed an association of SNPs in PNPLA3, PARVB, SAMM50 and PZP genes with NAFLD. SNPs in NCAN and PNPLA3gene were associated with higher levels of ALT,whereas variant SNPs in APOC3, PNPLA3, EFCAB4 B and COL13A1 were associated with high triglyceride levels.

Genetic polymorphisms in HIFIA are associated with prostate cancer risk in a Chinese population

The hypoxia-inducible factor-1α（HIF-1α） plays an important role in regulating angiogenesis, which is essential for tumor growth and metastasis. Genetic variations of HIFIA （coding HIF-1α） have been shown to influence an individual＇s susceptibility to many human tumors; however, evidence on associations between HIFIA single-nucleotide polymorphisms （SNPs） and prostate cancer （PCa） risk is conflicting. We genotyped three potentially functional polymorphisms in HIFIA （rs11549465, rs11549467 and rs2057482） using the TaqMan method and assessed their associations with PCa risk in a case-control study of 662 PCa patients and 716 controls in a Chinese Hart population. Compared with rs 11549467 GG genotype, the variant genotypes GA ＋AA had a significantly increased PCa risk （adjusted odds ratio （OR）= 1.70; 95% confidence interval （C1）= 1.06-2.72）, particularly among older patients （0R=2.01; 95%C1 = 1.05-3.86）, smokers （0R=2.06; 95%C1 = 1.07-3.99）, never drinkers （OR=2.16; 95%C1 = 1.20-3.86） and patients without a family history of cancer （OR= 1.71; 95%C1= 1.02-2.89）. Furthermore, patients with rs11549467 variant genotypes were associated with a higher Gleason score （OR=2.14; 95%CI = 1.22-3.75）. No altered PCa risk was associated with the rs 11549465 and rs2057482 polymorphism. However, the combined variant genotypes of rs2057482 and rs 11549467 were associated with increased PCa risk （0R=2.10; 95%C1= 1.23-3.57 among subjects carrying three or more risk alleles）. These results suggest that HIFIA polymorphisms may impact PCa susceptibility and progression in the Chinese Han population.

An approach to incorporate linkage disequilibrium structure into genomic association analysis

In this study, we propose to use the principal component analysis （PCA） and regression model to incorporate linkage disequilibrium （LD） in genomic association data analysis. To accommodate LD in genomic data and reduce multiple testing, we suggest performing PCA and extracting the PCA score to capture the variation of genomic data, after which regression analysis is used to assess the association of the disease with the principal component score. An empirical analysis result shows that both genotype-based correlation matrix and haplotype-based LD matrix can produce similar results for PCA. Principal component score seems to be more powerful in detecting genetic association because the principal component score is quantitatively measured and may be able to capture the effect of multiple loci.

Differences in clinical and genetic characteristics between early-and late-onset narcolepsy in a Han Chinese cohort

Early-and late-onset narcolepsy constitutes two distinct diagnostic subgroups.However,it is not clear whether symptomology and genetic risk factors differ between early-and late-onset narcoleptics.This study compared clinical data and single-nucleotide polymorphisms(SNPs)between early-and late-onset patients in a large cohort of 899 Han Chinese narcolepsy patients.Blood,cerebrospinal fluid,and clinical data were prospectively collected from patients,and patients were genotyped for 40 previously reported narcolepsy risk-conferring SNPs.Genetic risk scores(GRSs),associations of five different sets of SNPs(GRS1–GRS5)with early-and late-onset narcolepsy,were evaluated using logistic regression and receiver operating characteristic curves.Mean sleep latency was significantly shorter in early-onset cases than in late-onset cases.Symptom severity was greater among late-onset patients,with higher rates of sleep paralysis,hypnagogic hallucinations,health-related quality of life impairment,and concurrent presentation with four or more symptoms.Hypocretin levels did not differ significantly between early-and late-onset cases.Only rs3181077(CCR1/CCR3)and rs9274477(HLA-DQB1)were more prevalent among early-onset cases.Only GRS1(26 SNPs;OR=1.513,95%CI:0.893–2.585;P<0.05)and GRS5(6 SNPs;OR=1.893,95%CI:1.204–2.993;P<0.05)were associated with early-onset narcolepsy,with areas under the receiver operating characteristic curves of 0.731 and 0.732,respectively.Neither GRS1 nor GRS5 included SNPs in HLA regions.Our results indicate that symptomology and genetic risk factors differ between early-and late-onset narcolepsy.This protocol was approved by the Institutional Review Board(IRB)Panels on Medical Human Subjects at Peking University People’s Hospital,China(approval No.Yuanlunshenlinyi 86)in October 2011.

Genetic epidemiology of diabetic retinopathy

The disease burden of diabetic retinopathy(DR)is tremendous around the world.While DR is correlated with hemoglobin A1c(HbA1c)and duration of diabetes,genetic differences likely account for variation in susceptibility to DR.DR is a polygenic disorder with demonstrated heritability.However,linkage and admixture analyses,candidate gene association studies,and genome-wide association studies(GWAS)have not identified many loci for DR that can be consistently replicated.Larger,collaborative,multi-ethnic GWAS are needed to identify common variants with small effects.Rigorous defining of controls groups as patients with a long duration of diabetes without DR,and case groups as patients with severe DR will also aid in finding genes associated with DR.Replication in independent cohorts will be key to establishing associated loci for DR.Investigations of mitochondrial DNA and epigenetics in DR are ongoing.Whole exome sequencing presents new opportunities to identify rare variants that might be implicated in DR development.Continued research in the genetic epidemiology of DR is needed,with the potential to elucidate pathogenesis and treatment of an important disease.

An Adaptive Weighted Sum Test for Family-Based Multi-Marker Association Studies

Backgrounds: Although many disease-associated common variants have been discovered through genome-wide association studies, much of the genetic effects of complex diseases have not been explained. Population-based association studies are vulnerable to population stratification. A possible solution is to use family-based tests. However, if tests only estimate the genetic effect from the within-family variation to avoid population stratification, they may ignore the useful genetic information from between-family variation and lose power. Methods: We have developed an adaptive weighted sum test for family-based association studies. The new test uses data driven weights to combine two test statistics, and the weights measure the strength of population stratification. When population stratification is strong, the proposed test will automatically put more weight on one statistic derived from within-family variation to maintain robustness against spurious positives. On the other hand, when the effect of population stratification is relatively weak, the proposed test will automatically put more weight on the other statistic derived from both within-family and between-family variation to make use of both sources of genetic variation;and at the same time, the degrees of freedom of the test will be reduced and power of the test will be increased. Results: In our study, the proposed method achieves a higher power in most scenarios of linkage disequilibrium structure as well as Hap Map data from different genes under different population structures while still keeping its robustness against population stratification.

Implicit Hypotheses Are Hidden Power Droppers in Family-Based Association Studies of Secondary Outcomes

Family-based tests of association between a genetic marker and a disease constitute a common design to dissect the genetic architecture of complex traits. The FBAT software is one of the most popular tools to perform such studies. However, researchers are also often interested in the genetic contribution to a more specific manifestation of the phenotype (e.g. severe vs. non-severe form) known as a secondary outcome. Here, what we demonstrate is the limited power of the classical formulation of the FBAT statistic to detect the effect of genetic variants that influence a secondary outcome, in particular when these variants also impact on the onset of the disease, the primary outcome. We prove that this loss of power is driven by an implicit hypothesis, and we propose a derivation of the original FBAT statistic, free from this implicit hypothesis. Finally, we demonstrate analytically that our new statistic is robust and more powerful than FBAT for the detection of association between a genetic variant and a secondary outcome.

Genetic Variants in the ELOVL5 but not ELOVL2 Gene Associated with Polyunsaturated Fatty Acids in Han Chinese Breast Milk

The present study was designed to examine the contributions of the fatty acid elongase （ELOVL） gene polymorphisms to the levels of polyunsaturated fatty acids （PUFAs） in breast milk. Two hundred and nine healthy Han Chinese mothers were included in the study. Carriers of minor alleles of SNPs （rs2397142 and rs9357760） in ELOVL5 were associated with higher levels of linoleic acid （LA）, dihomo-γ-linolenic acid （DGLA）, arachidonic acid （AA）, docosatetraenoic acid （DTA）, docosahexenoic acid （DHA）, while in rs209512 of ELOVL5 the carriers of minor alleles had lower levels of DTA compared to major homozygote alleles （P ranged from 0.004-0.046）, and genetically explained variability ranged from 3.2% for eicosapentaenoic acid （EPA） to 6.0% for LA. Our findings demonstrated that common variation in ELOVL5 gene encoding rate-limiting enzymes in the metabolism of PUFAs contribute to the PUFAs in breast milk.

A Genetic Susceptibility Study of Lung Cancer Risk Potentially Associated with Polycyclic Aromatic Hydrocarbon Inhalation Exposure

For lifetime non-smokers, lung cancer risk is mainly associated with inhalation exposure to air pollution. For the Chinese population, indoor air pollution due to solid fuel combustion has been the primary source of inhalation exposure for decades. Polycyclic aromatic hydrocarbons （PAHs） are the by-products of incomplete combustion.