Displaying publications 1 - 20 of 72 in total

Abstract:
Sort:
  1. Li H, Teo YY, Tan EK
    Mov Disord, 2015 Sep;30(10):1335-42.
    PMID: 25758099 DOI: 10.1002/mds.26176
    Reproducing genomewide association studies findings in different populations is challenging, because the reproducibility fundamentally relies on the similar patterns of linkage disequilibrium between the unknown causal variants and the genotyped single-nucleotide polymorphisms (SNPs).
    Matched MeSH terms: European Continental Ancestry Group/genetics*
  2. Ismail R
    J Postgrad Med, 2006 Oct-Dec;52(4):245.
    PMID: 17243206
    Matched MeSH terms: European Continental Ancestry Group/genetics*
  3. Zainuddin Z, Teh LK, Suhaimi AW, Ismail R
    J Clin Pharm Ther, 2006 Apr;31(2):187-91.
    PMID: 16635054
    CYP2C9 is one of the major drug metabolizing enzymes for many drugs including warfarin, NSAIDs and losartan. It is polymorphic in many populations. Data on the distribution of CYP2C9 and the implication of CYP2C9 polymorphism in the Malaysian population is lacking. Our objectives were therefore to investigate the prevalence of CYP2C9 variants among unrelated healthy volunteers of Malays, Chinese and Indians in Malaysia.
    Matched MeSH terms: European Continental Ancestry Group/genetics
  4. Chang YM, Perumal R, Keat PY, Yong RY, Kuehn DL, Burgoyne L
    Forensic Sci Int, 2007 Mar 2;166(2-3):115-20.
    PMID: 16765004
    The use of STR multiplexes with the incorporated gender marker Amelogenin is common practice in forensic DNA analysis. However, when a known male sample shows a dropout of the Amelogenin Y-allele, the STR system falsely genotypes it as a female. To date, our laboratory has observed 18 such cases: 12 from our Y-STR database and six from casework. A study on 980 male individuals in the Malaysian population using the AmpFlSTR Y-filer has revealed a distinct Y-chromosome haplotype associated with the Amelogenin nulls. Our results showed that whilst the Amelogenin nulls were noticeably absent among the Chinese, both the Indians and Malays exhibited such mutations at 3.2 and 0.6%, respectively. It was also found that the Amelogenin negative individuals predominantly belonged to the J2e lineage, suggesting the possibility of a common ancestor for at least some of these chromosomes. The null frequencies showed concordance with the data published in Chang et al. [Higher failures of Amelogenin sex test in an Indian population group, J. Forensic Sci. 48 (2003) 1309-1313] on a smaller Malaysian population of 338 males which used a Y-STR triplex. In the current study, apart from the absence of the Amelogenin Y-locus, a complete absence of the DYS458 locus in all the nulls was also observed. This study together with the 2003 study has indicated a similar deletion region exists on the Y(p)11.2 band in all the 18 Y-chromosomes. Using bioinformatics, this deletion has been mapped to a region of at least 1.13 Mb on the Y(p)11.2 encompassing the Amelogenin, MSY1 minisatellite and DYS458 locus. Further, the Y-filer haplotypes revealed an additional null at Y-GATA H4 in two of the Indian males presented here.
    Matched MeSH terms: European Continental Ancestry Group/genetics
  5. Loh HC, Tang PY, Tee SF, Chow TJ, Choong CY, Lim SY, et al.
    Psychiatry Res, 2013 Jul 30;208(2):186-8.
    PMID: 23489597 DOI: 10.1016/j.psychres.2013.01.022
    Neuregulin-1 is widely investigated due to its hypothesised association with schizophrenia. Single-nucleotide polymorphisms rs764059, rs2954041 and rs3924999 were investigated (417 patients with schizophrenia and 429 controls). We failed to demonstrate a significant association between rs2954041 and rs3924999 with schizophrenia in the three ethnic groups studied (Malay, Chinese, and Indian), while rs764059 was found to be monomorphic.
    Matched MeSH terms: European Continental Ancestry Group/genetics
  6. Halder D, Dharap AS, Than M
    Anthropol Anz, 1999 Mar;57(1):69-75.
    PMID: 10320927
    Early identification of a syndrome at birth is of paramount importance for genetic counselling and possible prevention. Often malformation of the hands and fingers are cardinal manifestations of recognizable syndromes. As there are no published standards for hand and finger size for Malay newborn infants, this study was undertaken to establish normal values for hand, middle finger and palmar lengths, and their indices. A cross-sectional study was done on 509 consecutive newborn Malay babies between 34 and 42 weeks of gestation. Measurements were made on the right hand according to the recommended guidelines of Bergsma & Feingold (1975). The mean values for the measurements did not differ significantly between boys and girls, or change with gestation. For the whole group the mean value for total hand length was 64.4 +/- 3.42 mm, middle finger length 37.1 +/- 2.91 mm, palmar length 27.4 +/- 2.15 mm, finger index 0.425 +/- 0.03 and palmar index 0.58 +/- 0.03. A comparison with published measurements for newborns of different racial origin shows significant differences for the total hand length, middle finger length and palm length from Indian and Jewish infants, but not from Japanese infants. The indices were similar in Malay, Indian, Jewish and Japanese newborn infants.
    Matched MeSH terms: European Continental Ancestry Group/genetics
  7. Saha N
    Hum. Hered., 1991;41(1):47-52.
    PMID: 2050382
    A total of 627 subjects comprising 455 Chinese, 127 Dravidian Indians and 45 Malays were investigated for serum Apo A-IV polymorphism. The frequency of Apo A-IV*2 was found to be significantly higher (p less than 0.001) in Indians (0.043) compared to that in the Chinese (0.010) and Malays (0.011). The frequency of A-IV*3 was found to be around 0.02 in all the ethnic groups. A low frequency of A-IV*4 (less than 0.01) was observed in the Chinese and Indians. The phenotypic distribution of Apo A-IV was at Hardy-Weinberg equilibrium in the three ethnic groups.
    Matched MeSH terms: European Continental Ancestry Group/genetics
  8. Ali AO, Stear A, Fairlie-Clarke K, Brujeni GN, Isa NM, Salisi MS, et al.
    Immunogenetics, 2017 03;69(3):157-163.
    PMID: 27921144 DOI: 10.1007/s00251-016-0962-6
    Understanding the structure of the major histocompatibility complex, especially the number and frequency of alleles, loci and haplotypes, is crucial for efficient investigation of the way in which the MHC influences susceptibility to disease. Nematode infection is one of the most important diseases suffered by sheep, and the class II region has been repeatedly associated with differences in susceptibility and resistance to infection. Texel sheep are widely used in many different countries and are relatively resistant to infection. This study determined the number and frequency of MHC class II genes in a small flock of Texel sheep. There were 18 alleles at DRB1, 9 alleles at DQA1, 13 alleles at DQB1, 8 alleles at DQA2 and 16 alleles at DQB2. Several haplotypes had no detectable gene products at DQA1, DQB1 or DQB2, and these were defined as null alleles. Despite the large numbers of alleles, there were only 21 distinct haplotypes in the population. The relatively small number of observed haplotypes will simplify finding disease associations because common haplotypes provide more statistical power but complicate the discrimination of causative mutations from linked marker loci.
    Matched MeSH terms: European Continental Ancestry Group/genetics*
  9. Ismail R, Teh LK
    Eur J Clin Pharmacol, 2001 Oct;57(8):617-8.
    PMID: 11758642
    Matched MeSH terms: European Continental Ancestry Group/genetics*
  10. Bipolar Disorder and Schizophrenia Working Group of the Psychiatric Genomics Consortium. Electronic address: douglas.ruderfer@vanderbilt.edu, Bipolar Disorder and Schizophrenia Working Group of the Psychiatric Genomics Consortium
    Cell, 2018 Jun 14;173(7):1705-1715.e16.
    PMID: 29906448 DOI: 10.1016/j.cell.2018.05.046
    Schizophrenia and bipolar disorder are two distinct diagnoses that share symptomology. Understanding the genetic factors contributing to the shared and disorder-specific symptoms will be crucial for improving diagnosis and treatment. In genetic data consisting of 53,555 cases (20,129 bipolar disorder [BD], 33,426 schizophrenia [SCZ]) and 54,065 controls, we identified 114 genome-wide significant loci implicating synaptic and neuronal pathways shared between disorders. Comparing SCZ to BD (23,585 SCZ, 15,270 BD) identified four genomic regions including one with disorder-independent causal variants and potassium ion response genes as contributing to differences in biology between the disorders. Polygenic risk score (PRS) analyses identified several significant correlations within case-only phenotypes including SCZ PRS with psychotic features and age of onset in BD. For the first time, we discover specific loci that distinguish between BD and SCZ and identify polygenic components underlying multiple symptom dimensions. These results point to the utility of genetics to inform symptomology and potential treatment.
    Matched MeSH terms: European Continental Ancestry Group/genetics
  11. Darst BF, Shen J, Madduri RK, Rodriguez AA, Xiao Y, Sheng X, et al.
    Am J Hum Genet, 2023 Jul 06;110(7):1200-1206.
    PMID: 37311464 DOI: 10.1016/j.ajhg.2023.05.010
    Genome-wide polygenic risk scores (GW-PRSs) have been reported to have better predictive ability than PRSs based on genome-wide significance thresholds across numerous traits. We compared the predictive ability of several GW-PRS approaches to a recently developed PRS of 269 established prostate cancer-risk variants from multi-ancestry GWASs and fine-mapping studies (PRS269). GW-PRS models were trained with a large and diverse prostate cancer GWAS of 107,247 cases and 127,006 controls that we previously used to develop the multi-ancestry PRS269. Resulting models were independently tested in 1,586 cases and 1,047 controls of African ancestry from the California Uganda Study and 8,046 cases and 191,825 controls of European ancestry from the UK Biobank and further validated in 13,643 cases and 210,214 controls of European ancestry and 6,353 cases and 53,362 controls of African ancestry from the Million Veteran Program. In the testing data, the best performing GW-PRS approach had AUCs of 0.656 (95% CI = 0.635-0.677) in African and 0.844 (95% CI = 0.840-0.848) in European ancestry men and corresponding prostate cancer ORs of 1.83 (95% CI = 1.67-2.00) and 2.19 (95% CI = 2.14-2.25), respectively, for each SD unit increase in the GW-PRS. Compared to the GW-PRS, in African and European ancestry men, the PRS269 had larger or similar AUCs (AUC = 0.679, 95% CI = 0.659-0.700 and AUC = 0.845, 95% CI = 0.841-0.849, respectively) and comparable prostate cancer ORs (OR = 2.05, 95% CI = 1.87-2.26 and OR = 2.21, 95% CI = 2.16-2.26, respectively). Findings were similar in the validation studies. This investigation suggests that current GW-PRS approaches may not improve the ability to predict prostate cancer risk compared to the PRS269 developed from multi-ancestry GWASs and fine-mapping.
    Matched MeSH terms: European Continental Ancestry Group/genetics
  12. Wang A, Shen J, Rodriguez AA, Saunders EJ, Chen F, Janivara R, et al.
    Nat Genet, 2023 Dec;55(12):2065-2074.
    PMID: 37945903 DOI: 10.1038/s41588-023-01534-4
    The transferability and clinical value of genetic risk scores (GRSs) across populations remain limited due to an imbalance in genetic studies across ancestrally diverse populations. Here we conducted a multi-ancestry genome-wide association study of 156,319 prostate cancer cases and 788,443 controls of European, African, Asian and Hispanic men, reflecting a 57% increase in the number of non-European cases over previous prostate cancer genome-wide association studies. We identified 187 novel risk variants for prostate cancer, increasing the total number of risk variants to 451. An externally replicated multi-ancestry GRS was associated with risk that ranged from 1.8 (per standard deviation) in African ancestry men to 2.2 in European ancestry men. The GRS was associated with a greater risk of aggressive versus non-aggressive disease in men of African ancestry (P = 0.03). Our study presents novel prostate cancer susceptibility loci and a GRS with effective risk stratification across ancestry groups.
    Matched MeSH terms: European Continental Ancestry Group/genetics
  13. Szpak M, Mezzavilla M, Ayub Q, Chen Y, Xue Y, Tyler-Smith C
    Genome Biol, 2018 Jan 17;19(1):5.
    PMID: 29343290 DOI: 10.1186/s13059-017-1380-2
    We present a new method, Fine-Mapping of Adaptive Variation (FineMAV), which combines population differentiation, derived allele frequency, and molecular functionality to prioritize positively selected candidate variants for functional follow-up. We calibrate and test FineMAV using eight experimentally validated "gold standard" positively selected variants and simulations. FineMAV has good sensitivity and a low false discovery rate. Applying FineMAV to the 1000 Genomes Project Phase 3 SNP dataset, we report many novel selected variants, including ones in TGM3 and PRSS53 associated with hair phenotypes that we validate using available independent data. FineMAV is widely applicable to sequence data from both human and other species.
    Matched MeSH terms: European Continental Ancestry Group/genetics
  14. Yang Y, Wu L, Shu X, Lu Y, Shu XO, Cai Q, et al.
    Cancer Res, 2019 Feb 01;79(3):505-517.
    PMID: 30559148 DOI: 10.1158/0008-5472.CAN-18-2726
    DNA methylation is instrumental for gene regulation. Global changes in the epigenetic landscape have been recognized as a hallmark of cancer. However, the role of DNA methylation in epithelial ovarian cancer (EOC) remains unclear. In this study, high-density genetic and DNA methylation data in white blood cells from the Framingham Heart Study (N = 1,595) were used to build genetic models to predict DNA methylation levels. These prediction models were then applied to the summary statistics of a genome-wide association study (GWAS) of ovarian cancer including 22,406 EOC cases and 40,941 controls to investigate genetically predicted DNA methylation levels in association with EOC risk. Among 62,938 CpG sites investigated, genetically predicted methylation levels at 89 CpG were significantly associated with EOC risk at a Bonferroni-corrected threshold of P < 7.94 × 10-7. Of them, 87 were located at GWAS-identified EOC susceptibility regions and two resided in a genomic region not previously reported to be associated with EOC risk. Integrative analyses of genetic, methylation, and gene expression data identified consistent directions of associations across 12 CpG, five genes, and EOC risk, suggesting that methylation at these 12 CpG may influence EOC risk by regulating expression of these five genes, namely MAPT, HOXB3, ABHD8, ARHGAP27, and SKAP1. We identified novel DNA methylation markers associated with EOC risk and propose that methylation at multiple CpG may affect EOC risk via regulation of gene expression. SIGNIFICANCE: Identification of novel DNA methylation markers associated with EOC risk suggests that methylation at multiple CpG may affect EOC risk through regulation of gene expression.
    Matched MeSH terms: European Continental Ancestry Group/genetics*
  15. Hatta FH, Aklillu E
    OMICS, 2015 Dec;19(12):777-81.
    PMID: 26669712 DOI: 10.1089/omi.2015.0159
    CYP2C9 enzyme contributes to the metabolism of several pharmaceuticals and xenobiotics and yet displays large person-to-person and interethnic variation. Understanding the mechanisms of CYP2C9 variation is thus of immense importance for personalized medicine and rational therapeutics. A genetic variant of P450 (cytochrome) oxidoreductase (POR), a CYP450 redox partner, is reported to influence CYP2C9 metabolic activity in vitro. We investigated the impact of a common variant, POR*28, on CYP2C9 metabolic activity in humans. 148 healthy Swedish and 146 healthy Korean volunteers were genotyped for known CYP2C9 defective variant alleles (CYP2C9*2, *3). The CYP2C9 phenotype was determined using a single oral dose of 50 mg losartan. Excluding oral contraceptive (OC) users and carriers of 2C9*2 and *3 alleles, 117 Korean and 65 Swedish were genotyped for POR*5, *13 and *28 using Taqman assays. The urinary losartan to its metabolite E-3174 metabolic ratio (MR) was used as an index of CYP2C9 metabolic activity. The allele frequency of the POR*28 variant allele in Swedes and Koreans was 29% and 44%, respectively. POR*5 and *13 were absent in both study populations. Considering the CYP2C9*1/*1 genotypes only, the CYP2C9 metabolic activity was 1.40-fold higher in carriers of POR*28 allele than non-carriers among Swedes (p = 0.02). By contrast, no influence of the POR*28 on CYP2C9 activity was found in Koreans (p = 0.68). The multivariate analysis showed that ethnicity, POR genotype, and smoking were strong predictors of CYP2C9 MR (p < 0.05). This is the first report to implicate the importance of POR*28 genetic variation for CYP2C9 metabolic activity in humans. These findings contribute to current efforts for global personalized medicine and using medicines by taking into account pharmacogenetic and phenotypic variations.
    Matched MeSH terms: European Continental Ancestry Group/genetics*
  16. Li J, Lindström LS, Foo JN, Rafiq S, Schmidt MK, Pharoah PD, et al.
    Nat Commun, 2014 Jun 17;5:4051.
    PMID: 24937182 DOI: 10.1038/ncomms5051
    Large population-based registry studies have shown that breast cancer prognosis is inherited. Here we analyse single-nucleotide polymorphisms (SNPs) of genes implicated in human immunology and inflammation as candidates for prognostic markers of breast cancer survival involving 1,804 oestrogen receptor (ER)-negative patients treated with chemotherapy (279 events) from 14 European studies in a prior large-scale genotyping experiment, which is part of the Collaborative Oncological Gene-environment Study (COGS) initiative. We carry out replication using Asian COGS samples (n=522, 53 events) and the Prospective Study of Outcomes in Sporadic versus Hereditary breast cancer (POSH) study (n=315, 108 events). Rs4458204_A near CCL20 (2q36.3) is found to be associated with breast cancer-specific death at a genome-wide significant level (n=2,641, 440 events, combined allelic hazard ratio (HR)=1.81 (1.49-2.19); P for trend=1.90 × 10(-9)). Such survival-associated variants can represent ideal targets for tailored therapeutics, and may also enhance our current prognostic prediction capabilities.
    Matched MeSH terms: European Continental Ancestry Group/genetics
  17. Nazree NE, Loke AC, Zainal NZ, Mohamed Z
    Asia Pac Psychiatry, 2015 Mar;7(1):72-7.
    PMID: 24376086 DOI: 10.1111/appy.12118
    Numerous association studies of candidate genes studies with major depressive disorder (MDD) have been conducted for many years; however, the evidence of association between genes and the risk of developing MDD still remains inconclusive. In this study, we aimed to investigate the association between the tryptophan hydroxylase 2 (TPH2) gene and MDD in three ethnic groups (Malay, Chinese and Indian) within the Malaysian population.
    Matched MeSH terms: European Continental Ancestry Group/genetics
  18. Ang KC, Ngu MS, Reid KP, Teh MS, Aida ZS, Koh DX, et al.
    PLoS One, 2012;7(8):e42752.
    PMID: 22912732 DOI: 10.1371/journal.pone.0042752
    Pigmentation is a readily scorable and quantitative human phenotype, making it an excellent model for studying multifactorial traits and diseases. Convergent human evolution from the ancestral state, darker skin, towards lighter skin colors involved divergent genetic mechanisms in people of European vs. East Asian ancestry. It is striking that the European mechanisms result in a 10-20-fold increase in skin cancer susceptibility while the East Asian mechanisms do not. Towards the mapping of genes that contribute to East Asian pigmentation there is need for one or more populations that are admixed for ancestral and East Asian ancestry, but with minimal European contribution. This requirement is fulfilled by the Senoi, one of three indigenous tribes of Peninsular Malaysia collectively known as the Orang Asli. The Senoi are thought to be an admixture of the Negrito, an ancestral dark-skinned population representing the second of three Orang Asli tribes, and regional Mongoloid populations of Indo-China such as the Proto-Malay, the third Orang Asli tribe. We have calculated skin reflectance-based melanin indices in 492 Orang Asli, which ranged from 28 (lightest) to 75 (darkest); both extremes were represented in the Senoi. Population averages were 56 for Negrito, 42 for Proto-Malay, and 46 for Senoi. The derived allele frequencies for SLC24A5 and SLC45A2 in the Senoi were 0.04 and 0.02, respectively, consistent with greater South Asian than European admixture. Females and individuals with the A111T mutation had significantly lighter skin (p = 0.001 and 0.0039, respectively). Individuals with these derived alleles were found across the spectrum of skin color, indicating an overriding effect of strong skin lightening alleles of East Asian origin. These results suggest that the Senoi are suitable for mapping East Asian skin color genes.
    Matched MeSH terms: European Continental Ancestry Group/genetics
  19. Lim JS, Singh O, Ramasamy RD, Ramasamy S, Subramanian K, Lee EJ, et al.
    Drug Metab. Pharmacokinet., 2010;25(6):616-23.
    PMID: 20930417
    CYP1A2 play an important role in the metabolism of many carcinogens and clinically important drugs. CYP1A2 activity has been found to be influenced by the presence of polymorphic variants which were reported to display wide interethnic variation. This study investigates the frequency distribution and linkage disequilibrium patterns of CYP1A2 genetic polymorphisms, and characterize their haplotype structures in three healthy Asian populations in Singapore (Chinese, Malay, and Indian). The entire CYP1A2 gene was screened in 126 healthy subjects from all three ethnic groups (N=42 each). A total of 25 polymorphisms was identified, of which nine were novel. The polymorphisms, -2467delT and -163C>A were detected at high frequencies in all Asian ethnic groups. Significant interethnic differences were observed in the genotypic frequency distribution of IVS2-99G>A (P<0.01) and 1548C>T (P=0.05) across the three ethnic groups while -163C>A (P=0.02) was found to differ between Chinese and Malays. Haplotype analyses revealed four to six major haplotypes in each ethnic population which accounted for more than 60% of the cumulative haplotype frequencies. Future studies should be done to investigate the functional roles of these haplotypes.
    Matched MeSH terms: European Continental Ancestry Group/genetics*
  20. Lin PC, Lin WT, Yeh YH, Wung SF
    PLoS One, 2016;11(4):e0153044.
    PMID: 27058589 DOI: 10.1371/journal.pone.0153044
    BACKGROUND: There are racial and ethnic differences in the prevalence of gestational diabetes mellitus (GDM). Prior meta-analyses included small samples and very limited non-Caucasian populations. Studies to determine the relationship between transcription factor 7 like-2 (TCF7L2) rs7903146 polymorphism and risk of GDM in Hispanics/Latinos are recently available. The present meta-analysis was to estimate the impact of allele variants of TCF7L2 rs7903146 polymorphism on GDM susceptibility in overall population and racial/ethnic subgroups.

    METHODS: Literature was searched in multiple databases including PubMed, Web of Science, EMBASE (Ovid SP), Airiti Library, Medline Complete, and ProQuest up to July 2015. Allelic frequency for TCF7L2 rs7903146 polymorphism in GDM and control subjects was extracted and statistical analysis was performed using Comprehensive Meta-Analysis (CMA) 2.0 statistical software. The association between TCF7L2 rs7903146 polymorphism and GDM risk was assessed by pooled odd ratios (ORs) using five gene models (dominant, recessive, homozygote, heterozygote, and allele). Stratified analysis based on race/ethnicity was also conducted. The between-study heterogeneity and contribution of each single study to the final result was tested by Cochran Q test and sensitivity analyses, respectively. Publication bias was evaluated using Egger's linear regression test.

    RESULTS: A total of 16 studies involving 4,853 cases and 10,631 controls were included in this meta-analysis. Significant association between the T-allele of rs7903146 and GDM risk was observed under all genetic models, dominant model (OR = 1.44, 95% CI = 1.19-1.74), recessive model (OR = 1.35, 95% CI = 1.08-1.70), heterozygous model (OR = 1.31, 95% CI = 1.12-1.53), homozygous model (OR = 1.67, 95% CI = 1.31-2.12), and allele model (OR = 1.31, 95% CI = 1.12-1.53). Stratified analysis by race/ethnicity showed a statistically significant association between rs7903146 polymorphism and susceptibility to GDM under homozygous genetic model (TT versus CC) among whites, Hispanics/Latinos and Asians. Sensitivity analysis showed that the overall findings were robust to potentially influential decisions of the 16 studies included. No significant evidence for publication bias was observed in this meta-analysis for overall studies and subgroup studies.

    CONCLUSIONS: This meta-analysis showed that the T allele of TCF7L2 rs7903146 polymorphism was associated with susceptibility of GDM in overall population in white, Hispanic/Latino and Asian sub-groups. Asians with homozygous TT allele of rs7903146 polymorphism have highest risk of GDM (OR = 2.08) followed by Hispanics/Latinos (OR = 1.80) and whites (OR = 1.51). The highest and lowest frequency of T allele of rs7903146 was found in Malaysia and South Korea, respectively. Future studies are needed to profile genetic risk for GDM among high risk Asian and Pacific Islander subgroups.

    Matched MeSH terms: European Continental Ancestry Group/genetics
Filters
Contact Us

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links