• Genomics & Informatics
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• v.8 no.3
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• pp.103-107
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• 2010

The imputation of untyped SNPs enables researchers to validate association findings across SNP arrays and also enables them to test a large number of SNPs to reveal the fine structure of the association peak, facilitating interpretation of the results and the location of causal polymorphisms. In this study, we applied the imputation method to a genomewide association study and recapitulated the previously associated gene loci of blood pressure traits in Korean cohorts. A total of 1,827,004 SNPs were imputed by the IMPUTE program, and we conducted a genomewide association study for systolic and diastolic blood pressure. While no SNPs passed the Bonferroni correction p-value (p=$2.74{\times}10^{-8}$ for 1,827,004 SNPs), 12 novel loci for systolic blood pressure and 16 novel loci for diastolic blood pressure were detected by imputed SNPs, with $10^{-5}$ < p-value < $10^{-4}$. Moreover, 7 regions (ATP2B1, 10p15.1, ARHGEF12, ALX4, LIPC, 7q31.1, and TCF7L2) out of 14 genetic loci that were previously reported revealed that the imputed SNPs had lower p-values than those of genotyped SNPs. Moreover, a nonsynonymous SNP in the CSMD1 gene, one of the 14 genes, was found to be associated with systolic blood pressure (p<0.05). These results suggest that the imputation method can facilitate the discovery of novel SNPs as well as enhance the fine structure of the association peak in the loci.

• The Korean Journal of Physiology and Pharmacology
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• v.19 no.4
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• pp.319-325
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• 2015

Among solute carrier proteins, the organic anion transporters (OATs) play an important role for the elimination or reabsorption of endogenous and exogenous negatively charged anionic compounds. Among OATs, SLC22A9 (hOAT7) transports estrone sulfate with high affinity. The net decrease of estrogen, especially in post-menopausal women induces rapid bone loss. The present study was performed to search the SNP within exon regions of SLC22A9 in Korean females with osteoporosis. Fifty healthy controls and 50 osteoporosis patients were screened for the genetic polymorphism in the coding region of SLC22A9 using GC-clamped PCR and denaturing gradient gel electrophoresis (DGGE). Six SNPs were found on the SLC22A9 gene from Korean women with/without osteoporosis. The SNPs were located as follows: two SNPs in the osteoporosis group (A645G and T1277C), three SNPs in the control group (G1449T, C1467T and C1487T) and one SNP in both the osteoporosis and control groups (G767A). The G767A, T1277C and C1487T SNPs result in an amino acid substitution, from synonymous vs nonsynonymous substitution arginine to glutamine (R256Q), phenylalanine to serine (F426S) and proline to leucine (P496L), respectively. The Km values and Vmax of the wild type, R256Q, P496L and F426S were 8.84, 8.87, 9.83 and $12.74{\mu}M$, and 1.97, 1.96, 2.06 and 1.55 pmol/oocyte/h, respectively. The present study demonstrates that the SLC22A9 variant F426S is causing inter-individual variation that is leading to the differences in transport of the steroid sulfate conjugate (estrone sulfate) and, therefore this could be used as a marker for certain disease including osteoporosis.

• Genomics & Informatics
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• v.9 no.2
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• pp.64-68
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• 2011

Monomelic amyotrophy (MA), also known as Hirayama disease, occurs mainly in young men and manifests as weakness and wasting of the muscles of the distal upper limbs. Here, we sought to identify a genetic basis for MA. Given the predominance of MA in males, we focused on candidate neurological disease genes located on the X chromosome, selecting two X-linked candidate genes, androgen receptor (AR ) and ubiquitin-like modifier activating enzyme 1 (UBA1). Screening for genetic variants using patients' genomic DNA revealed three known genetic variants in the coding region of the AR gene: one nonsynonymous single-nucleotide polymorphism (SNP; rs78686797) encoding Leu57Gln, and two variants of polymorphic trinucleotide repeat segments that encode polyglutamine (CAG repeat; rs5902610) and polyglycine (GGC repeat; rs3138869) tracts. Notably, the Leu57Gln polymorphism was found in two patients with MA from 24 MA patients, whereas no variants were found in 142 healthy male controls. However, the numbers of CAG and GGC repeats in the AR gene were within the normal range. These data suggest that the Leu57Gln polymorphism encoded by the X-linked AR gene may contribute to the development of MA.

• Journal of Life Science
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• v.20 no.3
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• pp.462-465
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• 2010

Sweetness plays an important role in providing calories and promoting appetite for food. Since it has been known that genetic factor(s) is involved in individual differences in taste sensitivity in humans, this study aimed to examine genetic variations of the TAS1R2 gene, one of the components for tasting sweet compounds, by using DNA sequencing analysis from 98 unrelated Korean subjects. As a result, 12 different single nucleotide polymorphisms (SNPs) were identified in the hTAS1R2 gene and most of them were nonsynonymous. Also, two novel SNPs were found for the first time in this study. It was noted that the frequencies of these SNPs were common in the Korean population. 20 different haplotypes with coding SNPs (cSNPs) were also found in this study. Three out of these haplotypes were common, showing frequencies of > 10%. The repertoire and frequencies of cSNPs and haplotypes in the hTAS1R2 gene will provide information that will help identify a functional ligand receptor common in the Korean population.

• Genomics & Informatics
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• v.12 no.4
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• pp.187-194
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• 2014

Metabolic syndrome (METS) is a disorder of energy utilization and storage and increases the risk of developing cardiovascular disease and diabetes. To identify the genetic risk factors of METS, we carried out a genome-wide association study (GWAS) for 2,657 cases and 5,917 controls in Korean populations. As a result, we could identify 2 single nucleotide polymorphisms (SNPs) with genome-wide significance level p-values (< $5{\times}10^{-8}$), 8 SNPs with genome-wide suggestive p-values ($5{\times}10^{-8}{\leq}$ p < $1{\times}10^{-5}$), and 2 SNPs of more functional variants with borderline p-values ($5{\times}10^{-5}{\leq}$ p < $1{\times}10^{-4}$). On the other hand, the multiple correction criteria of conventional GWASs exclude false-positive loci, but simultaneously, they discard many true-positive loci. To reconsider the discarded true-positive loci, we attempted to include the functional variants (nonsynonymous SNPs [nsSNPs] and expression quantitative trait loci [eQTL]) among the top 5,000 SNPs based on the proportion of phenotypic variance explained by genotypic variance. In total, 159 eQTLs and 18 nsSNPs were presented in the top 5,000 SNPs. Although they should be replicated in other independent populations, 6 eQTLs and 2 nsSNP loci were located in the molecular pathways of LPL, APOA5, and CHRM2, which were the significant or suggestive loci in the METS GWAS. Conclusively, our approach using the conventional GWAS, reconsidering functional variants and pathway-based interpretation, suggests a useful method to understand the GWAS results of complex traits and can be expanded in other genomewide association studies.

• Genomics & Informatics
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• v.8 no.3
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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.

• Genes and Genomics
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• v.40 no.12
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• pp.1279-1285
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• 2018

Interdigitating dendritic cell sarcoma (IDCS) is an aggressive neoplasm and is an extremely rare disease, with a challenging diagnosis. Etiology of IDCS is also unknown and most studies with only case reports. In our case, immunohistochemistry showed that the tumor cells were positive for S100, CD45, and CD68, but negative for CD1a and CD21. This study aimed to investigate the causative factors of IDCS by sequencing the protein-coding regions of IDCS. We performed whole-exome sequencing with genomic DNA from blood and sarcoma tissue of the IDCS patient using the Illumina Hiseq 2500 platform. After that, we conducted Sanger sequencing for validation of sarcoma-specific variants and gene ontology analysis using DAVID bioinformatics resources. Through comparing sequencing data of sarcoma with normal blood, we obtained 15 nonsynonymous single nucleotide polymorphisms (SNPs) as sarcoma-specific variants. Although the 15 SNPs were not validated by Sanger sequencing due to tumor heterogeneity and low sensitivity of Sanger sequencing, we examined the function of the genes in which each SNP is located. Based on previous studies and gene ontology database, we found that POLQ encoding DNA polymerase theta enzyme and FNIP1 encoding tumor suppressor folliculin-interacting protein might have contributed to the IDCS. Our study provides potential causative genetic factors of IDCS and plays a role in advancing the understanding of IDCS pathogenesis.

• Genomics & Informatics
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• v.16 no.2
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• pp.36-41
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• 2018

Kawasaki disease (KD) is an acute febrile vasculitis predominately affecting infants and children. The dominant incidence age of KD is from 6 months to 5 years of age, and the incidence is unusual in those younger than 6 months and older than 5 years of age. We tried to identify genetic variants specifically associated with KD in patients younger than 6 months or older than 5 years of age. We performed an age-stratified genome-wide association study using the Illumina HumanOmni1-Quad BeadChip data (296 cases vs. 1,000 controls) and a replication study (1,360 cases vs. 3,553 controls) in the Korean population. Among 26 candidate single nucleotide polymorphisms (SNPs) tested in replication study, only a rare nonsynonymous SNP (rs4365796: c.1106C>T, p.Thr369Met) in the lymphoid enhancer binding factor 1 (LEF1) gene was very significantly associated with KD in patients younger than 6 months of age (odds ratio [OR], 3.07; $p_{combined}=1.10{\times}10^{-5}$), whereas no association of the same SNP was observed in any other age group of KD patients. The same SNP (rs4365796) in the LEF1 gene showed the same direction of risk effect in Japanese KD patients younger than 6 months of age, although the effect was not statistically significant (OR, 1.42; p = 0.397). This result indicates that the LEF1 gene may play an important role as a susceptibility gene specifically affecting KD patients younger than 6 months of age.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.7
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• pp.942-948
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• 2005

New polymorphism of major histocompatibility complex B-G genes was investigated by amplification and digestion of a 401bp fragment including intron 1 and exon 2 using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique with two restriction enzymes of Msp I and Tas I in eight breeds of Chinese indigenous chickens and one exotic breed. In the fragment region of the gene, three novel single nucleotide polymorphisms (SNPs) were detected at the two restriction sites. We found the transition of two nucleotides of A294G and T295C occurred at Tas I restriction site, and consequently led to a non-synonymous substitution of asparagine into serine at position 54 within the deduced amino acid sequence of immunoglobulin variable-region-like domain encoded by the exon 2 of B-G gene. It was observed at rare frequency that a single mutation of A294G occurring at the site, also caused an identical substitution of amino acid, asparagine 54-to-serine, to that we described previously. And the transversion of G319C at Msp I site led to a non-synonymous substitution, glutamine 62-to-histidine. The new alleles and allele frequencies identified by the PCR-RFLP method with the two enzymes were characterized, of which the allele A and B frequencies at Msp I and Tas I loci were given disequilibrium distribution either in the eight Chinese local breeds or in the exotic breed. By comparison, allele A at Msp I locus tended to be dominant, while, the allele B at Tas I locus tended to be dominant in all of the breeds analyzed. In Tibetan chickens, the preliminary association analysis revealed that no significant difference was observed between the different genotypes identified at the Msp I and Tas I loci and the laying performance traits, respectively.

• Molecules and Cells
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• v.38 no.5
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• pp.466-473
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• 2015

Over the last 30 years, Hanwoo has been selectively bred to improve economically important traits. Hanwoo is currently the representative Korean native beef cattle breed, and it is believed that it shared an ancestor with a Chinese breed, Yanbian cattle, until the last century. However, these two breeds have experienced different selection pressures during recent decades. Here, we whole-genome sequenced 10 animals each of Hanwoo and Yanbian cattle (20 total) using the Illumina HiSeq 2000 sequencer. A total of approximately 3.12 and 3.07 billion sequence reads were mapped to the bovine reference sequence assembly (UMD 3.1) at an average of approximately 10.71- and 10.53-fold coverage for Hanwoo and Yanbian cattle, respectively. A total of 17,936,399 single nucleotide polymorphisms (SNPs) were yielded, of which 22.3% were found to be novel. By annotating the SNPs, we further retrieved numerous nonsynonymous SNPs that may be associated with traits of interest in cattle. Furthermore, we performed whole-genome screening to detect signatures of selection throughout the genome. We located several promising selective sweeps that are potentially responsible for economically important traits in cattle; the PPP1R12A gene is an example of a gene that potentially affects intramuscular fat content. These discoveries provide valuable genomic information regarding potential genomic markers that could predict traits of interest for breeding programs of these cattle breeds.