• Genomics & Informatics
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• 제10권4호
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• pp.256-262
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• 2012

Most common complex traits, such as obesity, hypertension, diabetes, and cancers, are known to be associated with multiple genes, environmental factors, and their epistasis. Recently, the development of advanced genotyping technologies has allowed us to perform genome-wide association studies (GWASs). For detecting the effects of multiple genes on complex traits, many approaches have been proposed for GWASs. Multifactor dimensionality reduction (MDR) is one of the powerful and efficient methods for detecting high-order gene-gene ($G{\times}G$) interactions. However, the biological interpretation of $G{\times}G$ interactions identified by MDR analysis is not easy. In order to aid the interpretation of MDR results, we propose a network graph analysis to elucidate the meaning of identified $G{\times}G$ interactions. The proposed network graph analysis consists of three steps. The first step is for performing $G{\times}G$ interaction analysis using MDR analysis. The second step is to draw the network graph using the MDR result. The third step is to provide biological evidence of the identified $G{\times}G$ interaction using external biological databases. The proposed method was applied to Korean Association Resource (KARE) data, containing 8838 individuals with 327,632 single-nucleotide polymorphisms, in order to perform $G{\times}G$ interaction analysis of body mass index (BMI). Our network graph analysis successfully showed that many identified $G{\times}G$ interactions have known biological evidence related to BMI. We expect that our network graph analysis will be helpful to interpret the biological meaning of $G{\times}G$ interactions.

• Genomics & Informatics
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• 제12권4호
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• pp.181-186
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• 2014

Genome-wide association studies have proven the highly polygenic architecture of complex diseases or traits; therefore, single-locus-based methods are usually unable to detect all involved loci, especially when individual loci exert small effects. Moreover, the majority of associated single-nucleotide polymorphisms resides in non-coding regions, making it difficult to understand their phenotypic contribution. In this work, we studied epistatic interactions associated with three common diseases using Korea Association Resource (KARE) data: type 2 diabetes mellitus (DM), hypertension (HT), and coronary artery disease (CAD). We showed that epistatic single-nucleotide polymorphisms (SNPs) were enriched in enhancers, as well as in DNase I footprints (the Encyclopedia of DNA Elements [ENCODE] Project Consortium 2012), which suggested that the disruption of the regulatory regions where transcription factors bind may be involved in the disease mechanism. Accordingly, to identify the genes affected by the SNPs, we employed whole-genome multiple-cell-type enhancer data which discovered using DNase I profiles and Cap Analysis Gene Expression (CAGE). Assigned genes were significantly enriched in known disease associated gene sets, which were explored based on the literature, suggesting that this approach is useful for detecting relevant affected genes. In our knowledge-based epistatic network, the three diseases share many associated genes and are also closely related with each other through many epistatic interactions. These findings elucidate the genetic basis of the close relationship between DM, HT, and CAD.

• 대한의생명과학회지
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• 제18권3호
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• pp.244-253
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• 2012

Bone mineral density (BMD) is used in the clinical diagnosis of osteoporosis and the assessment of fracture risk. Osteoporosis, characterized mainly by decreased BMD, is a highly heritable complex disorder and a major public health concern to hundreds of millions of elderly persons worldwide. However, the specific genetic variants determining risk for low bone density are still largely unknown. Here, we performed association analysis to elucidate the possible relations of genetic polymorphisms in ESR1 gene with low bone density. By examining genotype data of a total of 1813 women in the Korean Association REsource (KARE) study, we discovered the ESR1 gene polymorphisms are associated with decreased BMD and osteoporosis. The results on the BD-RT (bone density estimated by T-score at distal radius), three SNPs (rs2248586, rs9371557, and rs1569788) within the ESR1 gene were significantly associated with bone density. The results on the BD-TT (bone density estimated by T-score at midshaft tibia), five SNPs (rs9371552, rs2248586, rs712221, rs7772475, and rs3798577) were significantly associated with bone density. The SNP rs2248586 within the ESR1 gene had commonly significance in both BD-RT (${\beta}$=-0.151, dominant P=0.049) and BD-TT (${\beta}$=-0.156, dominant P=0.039). In the SNP rs2248586, their ${\beta}$-values in BD-RT and/or BD-TT showed consistent trends with the odds ratios (ORs) of osteoporosis. In summary, we found statistically significant SNPs in ESR1 gene that are associated with both decreased BMD and osteoporosis traits. Therefore, our findings suggest ESR1 gene could be related to pathogenesis of osteoporosis.

• Genomics & Informatics
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• 제14권4호
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• pp.181-186
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• 2016

Glucose tolerance tests have been devised to determine the speed of blood glucose clearance. Diabetes is often tested with the standard oral glucose tolerance test (OGTT), along with fasting glucose level. However, no single test may be sufficient for the diagnosis, and the World Health Organization (WHO)/International Diabetes Federation (IDF) has suggested composite criteria. Accordingly, a single multi-class trait was constructed with three of the fasting phenotypes and 1- and 2-hour OGTT phenotypes from the Korean Association Resource (KARE) project, and the genetic association was investigated. All of the 18 possible combinations made out of the 3 sets of classification for the individual phenotypes were taken into our analysis. These were possible due to a method that was recently developed by us for estimating genomic associations using a generalized index of dissimilarity. Eight single-nucleotide polymorphisms (SNPs) that were found to have the strongest main effect are reported with the corresponding genes. Four of them conform to previous reports, located in the CDKAL1 gene, while the other 4 SNPs are new findings. Two-order interacting SNP pairs of are also presented. One pair (rs2328549 and rs6486740) has a prominent association, where the two single-nucleotide polymorphism locations are CDKAL1 and GLT1D1. The latter has not been found to have a strong main effect. New findings may result from the proper construction and analysis of a composite trait.

• 대한의생명과학회지
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• 제18권2호
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• pp.87-95
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• 2012

Hypertension is a complex disease that results from the interaction of genetic and environmental influences and heritability is influenced by about one-third to one-half. However, the specific genetic variants determining risk for hypertension are still largely unknown. Here, we performed association analysis to elucidate the possible relations of genetic polymorphisms in ESR1 gene with blood pressure traits. By examining genotype data of a total of 3,804 women in the Korean Association REsource (KARE) study, we discovered the ESR1 gene polymorphisms are associated with blood pressure and hypertension. The highest significant polymorphisms were rs2982571 (${\beta}=-1.56$, $P=6.8{\times}10^{-3}$) with systolic blood pressure (SBP), rs9322335 (${\beta}=-0.61$, P=0.013) with diastolic blood pressure (DBP), and rs851985 (OR=0.78, CI: 0.65~0.94, $P=8.6{\times}10^{-3}$) with hypertension. In the 5 SNPs (rs2982571, rs851985, rs851983, rs851981, and rs851980), their ${\beta}$-values in SBP and/or DBP showed consistent trends with the odds ratios (ORs) of hypertension, and these 5 SNPs were composed with one LD block. Consequently, we found statistically significant SNPs in ESR1 gene that are associated with both blood pressure and hypertension traits. These results suggested that the individuals with the minor alleles of the 5 SNPs in the ESR1 gene may be less susceptible to the development of hypertension in the Korean women.

• 대한의생명과학회지
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• 제18권4호
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• pp.377-383
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• 2012

Recent genome-wide association studies (GWAS) have identified a number of common variants associated with blood pressure homeostasis and hypertension in population. In the previous study, single nucleotide polymorphisms (SNPs) in the SLC4A4 gene have been reported to be associated with hypertension in Han Chinese population. We aimed to confirm whether the genetic variation of SLC4A4 gene influence the susceptibility to blood pressure and hypertension in Korean population. We genotyped variants in or near SLC4A4 in a population-based cohort including 7,551 unrelated Korean from Ansan and Ansung. Here, we performed association analysis to elucidate the possible relations of genetic polymorphisms in SLC4A4 gene with blood pressure traits. By examining genotype data of a total of 7,551 subjects in the Korean Association REsource (KARE) study, we discovered the SLC4A4 gene polymorphisms are associated with blood pressure and hypertension. The common and highest significant polymorphism was rs6846301 (${\beta}$=0.839, additive P=0.032) with systolic blood pressure (SBP), rs6846301 (${\beta}$=0.588, additive P=0.027) with diastolic blood pressure (DBP), and rs6846301 (OR=1.23, CI: 1.09~1.40, additive $P=1.2{\times}10^{-3}$) with hypertension. Furthermore, the SNP rs6846301 was consistently associated with both blood pressure and hypertension. Consequently, we found statistically significant SNPs in SLC4A4 gene that are associated with both blood pressure and hypertension traits. In addition, these results suggest that the individuals with the minor alleles of the SNP in the SLC4A4 gene may be more susceptible to the development of hypertension in the Korean population.

• 대한의생명과학회지
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• 제26권1호
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• pp.28-36
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• 2020

High blood pressure (HTN) is a condition in which blood pressure is kept higher than normal. Blood pressure trait measures systolic blood pressure (SBP) which is the highest pressure and diastolic blood pressure (DBP) which is the lowest blood pressure. Pulse pressure (PP) is the difference between systolic and diastolic blood pressure. Hypertension is known as a disease caused by the interaction of the environment and genetic factors. To date, studies have been conducted to find genes associated with hypertension. Genome-Wide Association Study (GWAS) analysis using European data from the UK Biobank reported new 535 loci were associated with blood pressure trait. Among them, 12 genes have been reported to have a significant correlation with SBP, DBP and PP. In the study, 12 genes polymorphisms were extracted based on KARE (Korean association resource) and then we performed linear regression of blood pressure trait. As a result, 6 SNPs of the 3 genes (rs12355413 and rs11006736 of ARMC4, rs2290883, rs2290884 and rs11039014 of LRP4, rs7234941 of BCL2) showed statistically significant correlation (P<0.05) with blood pressure trait. Of the 3 genes, 6 SNPs in 2 genes (rs9651357, rs12355413, rs11006736, rs1889522 of ARMC4 and rs4987774, rs7234941 of BCL2) showed significant correlation with hypertension. These results suggest that genetic polymorphisms of ARMC4, LRP4 and BCL2 genes are associated with blood pressure traits and hypertension in Korean population. Moreover, we expected to help understand the pathogenesis of hypertension.

• Genomics & Informatics
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• 제8권3호
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• pp.131-137
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• 2010

Genome-wide association studies (GWASs) have greatly contributed to the identification of common variants responsible for numerous complex traits. There are, however, unavoidable limitations in detecting causal and/or rare variants for traits in this approach, which depends on an LD-based tagging SNP microarray chip. In an effort to detect potential casual and/or rare variants for complex traits, such as type 2 diabetes (T2D) and triglycerides (TGs), we conducted a targeted resequencing of loci identified by the Korea Association REsource (KARE) GWAS. The target regions for resequencing comprised whole exons, exon-intron boundaries, and regulatory regions of genes that appeared within 1 Mb of the GWA signal boundary. From 124 individuals selected in population-based cohorts, a total of 0.7 Mb target regions were captured by the NimbleGen sequence capture 385K array. Subsequent sequencing, carried out by the Roche 454 Genome Sequencer FLX, generated about 110,000 sequence reads per individual. Mapping of sequence reads to the human reference genome was performed using the SSAHA2 program. An average of 62.2% of total reads was mapped to targets with an average 22X-fold coverage. A total of 5,983 SNPs (average 846 SNPs per individual) were called and annotated by GATK software, with 96.5% accuracy that was estimated by comparison with Affymetrix 5.0 genotyped data in identical individuals. About 51% of total SNPs were singletons that can be considered possible rare variants in the population. Among SNPs that appeared in exons, which occupies about 20% of total SNPs, 304 nonsynonymous singletons were tested with Polyphen to predict the protein damage caused by mutation. In total, we were able to detect 9 and 6 potentially functional rare SNPs for T2D and triglycerides, respectively, evoking a further step of replication genotyping in independent populations to prove their bona fide relevance to traits.

• 대한의생명과학회지
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• 제27권3호
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• pp.177-181
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• 2021

Allergy is an immune response that appears in certain people, and reactions such as coughing, shortness of breath, and hives occur. The immune system plays an important role in homeostasis and host defense, and allergies cause hypersensitivity reactions when an imbalance of immunity occurs. Mutations in the TLR genes are associated with autoimmune conditions such as allergies and asthma. It has been reported that a locus in the TLR1-TLR6-TLR10 region may be associated with atopic sensitization or allergy. Therefore, the purpose of this study was to select an allergy patient group and a healthy control group to determine how the genetic mutation of TLR1 affects the onset of disease. This study was conducted in 709 patients and 5,025 control groups out of 10,956 patients with data from KARE and HEXA cohorts. As a result of logistic regression analysis of 6 SNPs selected from the TLR1 gene, only rs117033348 showed a statistically significant correlation (P = 0.002356). The influence of rs117033348 was examined using PolyPhen-2, and a significant result was shown. Therefore, it can be predicted that the G base in rs117033348 will have an influence on the human body. In addition, Geography of Genetic Variants browser was used to confirm the geographical distribution of allele frequencies for the TLR1 gene. Although it was found that there was a large racial difference in the prevalence of TLR1 SNP, it could be confirmed that the polymorphism of rs117033348 conducted in this study was only specific in East Asia when compared with each race.

• 대한임상검사과학회지
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• 제51권3호
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• pp.323-328
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• 2019

결핵균에 의한 만성 세균성 감염인 결핵은 결핵균의 특성, 숙주의 면역상태와 유전적 감수성의 차이에 의해 잠복성과 활동성으로의 진행정도에 차이가 있다. 결핵균에 대한 숙주 방어 기전은 주로 대식세포, T 세포 및 수지상 세포 사이의 상호 작용에 기인한다. CD44는 결핵균에 감염되면 활성 T 세포에서 발현되며 림프구 이동을 조절한다. 또한 CD44는 ECM에 대한 백혈구의 부착을 매개하여 대식세포, CD4+ T cell 등을 폐로 불러모으는 역할을 한다. 따라서, CD44 유전자의 다형성은 결핵균에 대한 숙주세포의 면역기전 저하를 유발할 수 있다. 이 연구의 목적은 CD44 유전자의 유전자 다형성이 결핵의 감수성에 영향을 미치는지 조사하는 것이다. 결핵균과 CD44의 연관성에 대하여 대한 한국 협회 자원의 443명의 cases와 3228명의 control을 이용하여 CD44 유전자의 237개의 SNP를 분석하였다. 이 중 17개의 SNP가 결핵과 통계적으로 유의한 관련성을 보였다. 가장 유의성 있는 SNP는 rs75137824였다(OR=0.231, CI: 1.51~3.56, $P=1.3{\times}10^{-4}$). 또한 결핵 발병에 유의성이 있는 SNP중 rs10488809의 경우는 전사인자 JUND 및 FOS에 결합하는 부위로써 CD44 유전자 발현에 영향을 줄 수 있는 것으로 확인할 수 있었다. 이러한 결과는 결핵 발병이 CD44 발현 차이에 의한 숙주 면역반응에 차이에 의해서 감수성의 차이가 있을 수 있음을 나타 낼 수 있다. 이번 연구 결과는 결핵균 감염에 대한 숙주면역의 유전적 차이가 결핵 진행정도의 차이를 유발할 수 있다는 유전적 배경에 대한 기반을 마련해 줄 수 있을 것이라고 기대한다.