Displaying publications 301 - 320 of 355 in total

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  1. Gunaletchumy SP, Seevasant I, Tan MH, Croft LJ, Mitchell HM, Goh KL, et al.
    Sci Rep, 2014 Dec 11;4:7431.
    PMID: 25503415 DOI: 10.1038/srep07431
    Helicobacter pylori infection results in diverse clinical conditions ranging from chronic gastritis and ulceration to gastric adenocarcinoma. Among the multiethnic population of Malaysia, Indians consistently have a higher H. pylori prevalence as compared with Chinese and Malays. Despite the high prevalence of H. pylori, Indians have a relatively low incidence of peptic ulcer disease and gastric cancer. In contrast, gastric cancer and peptic ulcer disease incidence is high in Chinese. H. pylori strains from Chinese strains predominantly belong to the hspEAsia subpopulation while Indian/Malay strains mainly belong to the hspIndia subpopulation. By comparing the genome of 27 Asian strains from different subpopulations, we identified six genes associated with risk of H. pylori-induced peptic ulcer disease and gastric cancer. This study serves as an important foundation for future studies aiming to understand the role of bacterial factors in H. pylori-induced gastro-duodenal diseases.
    Matched MeSH terms: Genetic Association Studies
  2. Chung WH, Chang WC, Lee YS, Wu YY, Yang CH, Ho HC, et al.
    JAMA, 2014 Aug 6;312(5):525-34.
    PMID: 25096692 DOI: 10.1001/jama.2014.7859
    The antiepileptic drug phenytoin can cause cutaneous adverse reactions, ranging from maculopapular exanthema to severe cutaneous adverse reactions, which include drug reactions with eosinophilia and systemic symptoms, Stevens-Johnson syndrome, and toxic epidermal necrolysis. The pharmacogenomic basis of phenytoin-related severe cutaneous adverse reactions remains unknown.
    Matched MeSH terms: Genome-Wide Association Study
  3. Lee PC, Lam HH, Ghani SA, Subrayan V, Chua KH
    Genet. Mol. Res., 2014;13(2):3553-9.
    PMID: 24737507 DOI: 10.4238/2014.March.24.15
    Mutations in the PAX6 gene that cause aniridia have been identified in various ethnicities but not in the Malaysian population. Therefore, the objective of this study was to investigate the PAX6 mutation in a Malaysian family with congenital aniridia. In this study, a complete ophthalmic examination was performed on a Dusun ethnic family with aniridia. Genomic DNA was extracted from the peripheral blood of the subjects and screened for the PAX6 gene mutation using polymerase chain reaction amplification high-resolution melting curve analysis (PCR-HRM) followed by confirmation via direct DNA sequencing. A heterozygous G deletion (c.857delG) in exon 7 causing a frame shift in PAX6 was identified in all affected family members. Genotype-phenotype correlation analysis revealed congenital cataract and all affected family members showed a similar spectrum of aniridia with no phenotypic variability but with differences in severity that were age-dependent. In summary, by using a PCR-HRM approach, this study is the first to report a PAX6 mutation in a Malaysian family. This mutation is the cause of the aniridia spectra observed in this family and of congenital cataract.
    Matched MeSH terms: Genetic Association Studies
  4. Song YZ, Zhang ZH, Lin WX, Zhao XJ, Deng M, Ma YL, et al.
    PLoS One, 2013;8(9):e74544.
    PMID: 24069319 DOI: 10.1371/journal.pone.0074544
    The human SLC25A13 gene encodes citrin, the liver-type mitochondrial aspartate/glutamate carrier isoform 2 (AGC2), and SLC25A13 mutations cause citrin deficiency (CD), a disease entity that encompasses different age-dependant clinical phenotypes such as Adult-onset Citrullinemia Type II (CTLN2) and Neonatal Intrahepatic Cholestasis caused by Citrin Deficiency (NICCD). The analyses of SLC25A13 gene and its protein/mRNA products remain reliable tools for the definitive diagnoses of CD patients, and so far, the SLC25A13 mutation spectrum in Chinese CD patients has not been well-characterized yet.
    Matched MeSH terms: Genetic Association Studies
  5. Haerian BS, Baum L, Tan HJ, Kwan P, Raymond AA, Saruwatari J, et al.
    Pharmacogenomics, 2012 Oct;13(13):1477-85.
    PMID: 23057548 DOI: 10.2217/pgs.12.127
    Approximately 30% of epilepsy patients do not response to antiepileptic drugs (AEDs). The functional SCN1A IVS5N+5 polymorphism may play a role in response to some AEDs. The purpose of this study was to examine this hypothesis in a cohort study of Malaysian and Hong Kong Chinese epilepsy patients on sodium valproate (VPA) monotherapy and in a meta-analysis.
    Matched MeSH terms: Genetic Association Studies
  6. Vui-Kee K, Mohd Dali AZ, Mohamed Rose I, Ghazali R, Jamal R, Mokhtar NM
    Kaohsiung J. Med. Sci., 2012 May;28(5):243-50.
    PMID: 22531302 DOI: 10.1016/j.kjms.2011.11.007
    Nonepithelial ovarian cancer (NEOC) is a rare cancer that is often misdiagnosed as other malignant tumors. Research on this cancer using fresh tissues is nearly impossible because of its limited number of samples within a limited time provided. The study is to identify potential genes and their molecular pathways related to NEOC using formalin-fixed paraffin embedded samples. Total RNA was extracted from eight archived NEOCs and seven normal ovaries. The RNA samples with RNA integrity number >2.0, purity >1.7 and cycle count value <28 cycles were hybridized to the Illumina Whole-Genome DASL assay (cDNA-mediated annealing, selection, extension, and ligation). We analyzed the results using the GeneSpring GX11.0 and FlexArray software to determine the differentially expressed genes. Microarray results were validated using an immunohistochemistry method. Statistical analysis identified 804 differentially expressed genes with 443 and 361 genes as overexpressed and underexpressed in cancer, respectively. Consistent findings were documented for the overexpression of eukaryotic translation elongation factor 1 alpha 1, E2F transcription factor 2, and fibroblast growth factor receptor 3, except for the down-regulated gene, early growth response 1 (EGR1). The immunopositivity staining for EGR1 was found in the majority of cancer tissues. This finding suggested that the mRNA level of a transcript did not always match with the protein expression in tissues. The current gene profile can be the platform for further exploration of the molecular mechanism of NEOC.
    Matched MeSH terms: Genome-Wide Association Study
  7. Muthusamy KA, Lian LH, Vairavan N, Chua KH, Waran V
    Genet. Mol. Res., 2012;11(3):2939-45.
    PMID: 22782629
    Studies of genetic mutations that have been used in predicting glioma prognosis have revealed a complex relationship between clinical and genetic factors. Epidermal growth factor (EGF) and the NAT2 gene play a central role in carcinogenesis. An adenine (A) to guanine (G) single nucleotide polymorphism at position 61 in the 5'-untranslated region (5'-UTR) of the EGF gene has been found to be associated with levels of EGF production, and the mutations in the NAT2 gene have been postulated as a risk factor for cancer. We investigated EGF and the NAT2 gene in 13 glioma tissue samples and 12 normal controls. In the EGF 5'-UTR 61G polymorphism, the heterozygote GA was the most common genotype in the glioma patients. In the NAT2 polymorphism at nucleotide position 857G/A, the G allele and the GG genotype were the most prevalent forms in both the glioma and normal samples. We did not find any homozygous AA genotypes in the glioma patients. Based on this preliminary evidence, the EGF 5'-UTR at position 61 and the NAT2 SNP at position 857 polymorphisms are associated with increased risk for glioma.
    Matched MeSH terms: Genetic Association Studies
  8. Naidu R, Har YC, Taib NA
    APMIS, 2011 Jul;119(7):460-7.
    PMID: 21635553 DOI: 10.1111/j.1600-0463.2011.02753.x
    In the present study, we evaluated the association between the TP53BP1 Glu353Asp and T-885G polymorphisms and breast cancer risk as well as with the clinicopathological characteristics of the patients. Genotyping of these polymorphisms was performed on 387 breast cancer patients and 252 normal and healthy women who had no history of any malignancy using PCR-RFLP method in a hospital-based Malaysian population. Breast cancer risk was not observed among women who were heterozygous (OR(adj) = 0.887; 95% CI, 0.632-1.245) or homozygous (OR(adj) = 1.083; 95% CI, 0.595-1.969) for Asp allele, and those carriers of Asp allele (OR(adj) = 0.979; 95% CI, 0.771-1.243). Similarly, women who were TG heterozygotes (OR(adj) = 1.181; 95% CI, 0.842-1.658) or GG homozygotes (OR(adj) = 1.362; 95% CI, 0.746-2.486) and carriers of G allele (OR(adj) = 1.147; 95% CI, 0.903-1.458) were not associated with increased risk of breast cancer. Asp allele genotype was significantly associated with ER negativity (p = 0.0015) and poorly differentiated tumours (p = 0.008), but G allele genotype was not associated with the clinicopathological characteristics. In conclusion, Glu353Asp and T-885G polymorphic variants might not have an influence on breast cancer risk, thus might not be potential candidates for cancer susceptibility. Glu353Asp variant might be associated with tumour aggressiveness as defined by its association with ER negativity and poorly differentiated tumours.
    Matched MeSH terms: Genome-Wide Association Study
  9. Dorajoo R, Blakemore AI, Sim X, Ong RT, Ng DP, Seielstad M, et al.
    Int J Obes (Lond), 2012 Jan;36(1):159-63.
    PMID: 21544081 DOI: 10.1038/ijo.2011.86
    Recent genome-wide association studies (GWAS) have identified 38 obesity-associated loci among European populations. However, their contribution to obesity in other ethnicities is largely unknown.
    Matched MeSH terms: Genome-Wide Association Study
  10. Chai HC, Phipps ME, Chua KH
    Clin. Dev. Immunol., 2012;2012:963730.
    PMID: 21941582 DOI: 10.1155/2012/963730
    SLE is an autoimmune disease that is not uncommon in Malaysia. In contrast to Malays and Indians, the Chinese seem to be most affected. SLE is characterized by deficiency of body's immune response that leads to production of autoantibodies and failure of immune complex clearance. This minireview attempts to summarize the association of several candidate genes with risk for SLE in the Malaysian population and discuss the genetic heterogeneity that exists locally in Asians and in comparison with SLE in Caucasians. Several groups of researchers have been actively investigating genes that are associated with SLE susceptibility in the Malaysian population by screening possible reported candidate genes across the SLE patients and healthy controls. These candidate genes include MHC genes and genes encoding complement components, TNF, FcγR, T-cell receptors, and interleukins. However, most of the polymorphisms investigated in these genes did not show significant associations with susceptibility to SLE in the Malaysian scenario, except for those occurring in MHC genes and genes coding for TNF-α, IL-1β, IL-1RN, and IL-6.
    Matched MeSH terms: Genetic Association Studies
  11. Maran S, Lee YY, Xu SH, Raj MS, Abdul Majid N, Choo KE, et al.
    J Dig Dis, 2013 Apr;14(4):196-202.
    PMID: 23241512 DOI: 10.1111/1751-2980.12023
    To identify gene polymorphisms that differ between Malays, Han Chinese and South Indians, and to identify candidate genes for the investigation of their role in protecting Malays from Helicobacter pylori (H. pylori) infection.
    Matched MeSH terms: Genome-Wide Association Study
  12. Ong-Abdullah M, Ordway JM, Jiang N, Ooi SE, Kok SY, Sarpan N, et al.
    Nature, 2015 Sep 24;525(7570):533-7.
    PMID: 26352475 DOI: 10.1038/nature15365
    Somaclonal variation arises in plants and animals when differentiated somatic cells are induced into a pluripotent state, but the resulting clones differ from each other and from their parents. In agriculture, somaclonal variation has hindered the micropropagation of elite hybrids and genetically modified crops, but the mechanism responsible remains unknown. The oil palm fruit 'mantled' abnormality is a somaclonal variant arising from tissue culture that drastically reduces yield, and has largely halted efforts to clone elite hybrids for oil production. Widely regarded as an epigenetic phenomenon, 'mantling' has defied explanation, but here we identify the MANTLED locus using epigenome-wide association studies of the African oil palm Elaeis guineensis. DNA hypomethylation of a LINE retrotransposon related to rice Karma, in the intron of the homeotic gene DEFICIENS, is common to all mantled clones and is associated with alternative splicing and premature termination. Dense methylation near the Karma splice site (termed the Good Karma epiallele) predicts normal fruit set, whereas hypomethylation (the Bad Karma epiallele) predicts homeotic transformation, parthenocarpy and marked loss of yield. Loss of Karma methylation and of small RNA in tissue culture contributes to the origin of mantled, while restoration in spontaneous revertants accounts for non-Mendelian inheritance. The ability to predict and cull mantling at the plantlet stage will facilitate the introduction of higher performing clones and optimize environmentally sensitive land resources.
    Matched MeSH terms: Genetic Association Studies
  13. Chang CC, Ng CC, Too CL, Choon SE, Lee CK, Chung WH, et al.
    Pharmacogenomics J, 2017 03;17(2):170-173.
    PMID: 26927288 DOI: 10.1038/tpj.2016.10
    Phenytoin (PHT) is a common cause of severe cutaneous adverse reactions (SCARs), including Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN) and drug reaction with eosinophilia and systemic symptoms (DRESS). Although HLA-B*15:02 is associated with PHT-induced SJS/TEN (PHT-SJS/TEN) in Han Chinese and Thais, the genetic basis for susceptibility to PHT-induced SCARs (PHT-SCAR) in other populations remains unclear. We performed a case-control association study by genotyping the human leukocyte antigen (HLA)-B alleles of 16 Malay PHT-SCAR patients (13 SJS/TEN and 3 DRESS), 32 PHT-tolerant controls and 300 healthy ethnicity-matched controls. A novel genetic biomarker, HLA-B*15:13, showed significant association with PHT-SJS/TEN (53.8%, 7/13 cases) (odds ratio (OR) 11.28, P=0.003) and PHT-DRESS (100%, 3/3 cases) (OR 59.00, P=0.003) when compared with PHT-tolerant controls (9.4%, 3/32 controls). We also confirmed HLA-B*15:02 association with PHT-SJS/TEN (61.5%, 8/13 cases vs 21.9%, 7/32 controls; OR 5.71, P=0.016) when compared with PHT-tolerant controls. These alleles may serve as markers to predict PHT-SCAR in Malays.
    Matched MeSH terms: Genetic Association Studies
  14. Wei LK, Au A, Menon S, Gan SH, Griffiths LR
    J Stroke Cerebrovasc Dis, 2015 Sep;24(9):2017-25.
    PMID: 26187788 DOI: 10.1016/j.jstrokecerebrovasdis.2015.04.011
    The purpose of this study was threefold. First, it was to determine the relationship between serum vitamin profiles and ischemic stroke. The second purpose was to investigate the association of methylenetetrahydrofolate reductase (MTHFR), endothelial nitric oxide synthase (eNOS), angiotensin converting enzyme (ACE), and apolipoprotein-E (ApoE) gene polymorphisms with ischemic stroke and further correlate with serum vitamin profiles among ischemic stroke patients. The third purpose of the study was to highlight the interaction of MTHFR and eNOS haplotypes with serum vitamin profiles and ischemic stroke risks.
    Matched MeSH terms: Genetic Association Studies
  15. Chornokur G, Lin HY, Tyrer JP, Lawrenson K, Dennis J, Amankwah EK, et al.
    PLoS One, 2015;10(6):e0128106.
    PMID: 26091520 DOI: 10.1371/journal.pone.0128106
    BACKGROUND: Defective cellular transport processes can lead to aberrant accumulation of trace elements, iron, small molecules and hormones in the cell, which in turn may promote the formation of reactive oxygen species, promoting DNA damage and aberrant expression of key regulatory cancer genes. As DNA damage and uncontrolled proliferation are hallmarks of cancer, including epithelial ovarian cancer (EOC), we hypothesized that inherited variation in the cellular transport genes contributes to EOC risk.

    METHODS: In total, DNA samples were obtained from 14,525 case subjects with invasive EOC and from 23,447 controls from 43 sites in the Ovarian Cancer Association Consortium (OCAC). Two hundred seventy nine SNPs, representing 131 genes, were genotyped using an Illumina Infinium iSelect BeadChip as part of the Collaborative Oncological Gene-environment Study (COGS). SNP analyses were conducted using unconditional logistic regression under a log-additive model, and the FDR q<0.2 was applied to adjust for multiple comparisons.

    RESULTS: The most significant evidence of an association for all invasive cancers combined and for the serous subtype was observed for SNP rs17216603 in the iron transporter gene HEPH (invasive: OR = 0.85, P = 0.00026; serous: OR = 0.81, P = 0.00020); this SNP was also associated with the borderline/low malignant potential (LMP) tumors (P = 0.021). Other genes significantly associated with EOC histological subtypes (p<0.05) included the UGT1A (endometrioid), SLC25A45 (mucinous), SLC39A11 (low malignant potential), and SERPINA7 (clear cell carcinoma). In addition, 1785 SNPs in six genes (HEPH, MGST1, SERPINA, SLC25A45, SLC39A11 and UGT1A) were imputed from the 1000 Genomes Project and examined for association with INV EOC in white-European subjects. The most significant imputed SNP was rs117729793 in SLC39A11 (per allele, OR = 2.55, 95% CI = 1.5-4.35, p = 5.66x10-4).

    CONCLUSION: These results, generated on a large cohort of women, revealed associations between inherited cellular transport gene variants and risk of EOC histologic subtypes.

    Matched MeSH terms: Genetic Association Studies
  16. Kong AN, Fong CY, Ng CC, Mohamed AR, Khoo TB, Ng RL, et al.
    Seizure, 2020 Jul;79:103-111.
    PMID: 32464532 DOI: 10.1016/j.seizure.2020.05.009
    PURPOSE: Children with epilepsy (CWE) are at risk of vitamin D deficiency. Single nucleotide polymorphisms (SNPs) affecting the vitamin D pathway are potentially important risk factors for serum 25-hydroxyvitamin D [25(OH)D] concentration. The aims of our study were to evaluate the association of vitamin d-related SNPs to serum 25(OH)D concentrations in Malaysian CWE.

    METHODS: Cross-sectional study of Malaysian ambulant CWE on antiseizure medication for >1 year. Sixteen SNPs in 8 genes (GC, VDR, CYP2R1, CYP24A1, CYP27B1, CYP27A1, CYP3A4, NADSYN1/DHCR7) were genotyped. Linear and logistic regression models and co-variates adjusted analyses were used. SNPs with significant associations were further analysed in a group of ethnically-matched healthy Malaysian children.

    RESULTS: 239 CWE were recruited (52.7% Malay, 24.3% Chinese and 23.0% Indian) with mean serum 25(OH)D of 58.8 nmol/L (SD 25.7). Prevalence of vitamin D deficiency (≤37.5 nmol/L) was 23.0%. Minor allele of GC-rs4588-A was associated with lower serum 25(OH)D in the meta-analysis of both CWE (β -8.11, P = 0.002) and Malaysian healthy children (β -5.08, P < 0.001), while VDR-rs7975232-A was significantly associated with reduced odds of vitamin D deficiency in Malay subgroup of CWE (OR: 0.16; 95% CI: 0.06-0.49; P = 0.001) and this association was not found in the healthy children group.

    CONCLUSIONS: Our results suggest that GC-rs4588 is associated with lower serum 25(OH)D concentration in both Malaysian CWE and healthy children, while VDR-rs7975232A is associated with lower risk of vitamin D deficiency in Malaysian CWE of Malay ethnicity. Our findings may assist in the genetic risk stratification of low vitamin D status among CWE.

    Matched MeSH terms: Genetic Association Studies
  17. Ng ZX, Kuppusamy UR, Tajunisah I, Fong KC, Chua KH
    J Diabetes Complications, 2012 Sep-Oct;26(5):388-92.
    PMID: 22795339 DOI: 10.1016/j.jdiacomp.2012.05.014
    PURPOSE:
    In this study, we aimed to investigate the possible association between SLC2A1 26177A/G polymorphism and diabetic retinopathy (DR) in Malaysian patients with type 2 diabetes.

    METHODS:
    Genomic DNA was extracted from 211 Malaysian type 2 diabetic patients (100 without retinopathy [DNR], 111 with retinopathy) and 165 healthy controls. A high resolution melting assay developed in this study was used to detect SLC2A1 26177A/G polymorphism followed by statistical analysis.

    RESULTS:
    A statistically significant difference in 26177G minor allele frequency between healthy controls (19.7 %) and total patient group (26.1 %) (p<0.05, Odd ratio = 1.437, 95% Confidence interval = 1.015-2.035) as well as between healthy controls (19.7 %) and DNR patients (27.5%) (p<0.05, Odd ratio = 1.546, 95% Confidence interval = 1.024-2.336) was shown in this study. However, when compared between DR and DNR patients, there was no significant difference (p>0.05).

    CONCLUSIONS:
    This is the first study which shows that SLC2A1 26177G allele is associated with type 2 diabetes in Malaysian population but not with DR.
    Matched MeSH terms: Genetic Association Studies
  18. Naidu R, Har YC, Taib NA
    Scand J Clin Lab Invest, 2011 Oct;71(6):500-6.
    PMID: 21745146 DOI: 10.3109/00365513.2011.590223
    The purpose of this study was to investigate the association between the peptidyl-propyl-cis/trans isomerase 1 (PIN1) -842(G > C) and -667(T > C) polymorphic variants and breast cancer risk among Malaysian ethnic groups namely the Malays, Chinese and Indians, as well as clinico-pathological characteristics of the patients.
    Matched MeSH terms: Genetic Association Studies
  19. Saif-Ali R, Harun R, Kamaruddin NA, Al-Jassabi S, Ngah WZ
    Biochem Genet, 2012 Apr;50(3-4):298-308.
    PMID: 21983932 DOI: 10.1007/s10528-011-9472-2
    This study investigated the association of hepatocyte nuclear factor 4 (HNF4) alpha single nucleotide polymorphisms (SNPs) with type 2 diabetes with or without metabolic syndrome in Malaysia. Nine HNF4 alpha SNPs were genotyped in 390 type 2 diabetic subjects with metabolic syndrome, 135 type 2 diabetic subjects without metabolic syndrome, and 160 control subjects. The SNPs rs4810424, rs1884613, and rs2144908 were associated with protection against type 2 diabetes without metabolic syndrome (recessive P = 0.018, OR 0.32; P = 0.004, OR 0.25; P = 0.005, OR 0.24, respectively). The 6-SNP haplotype2 CCCGTC containing the risk genotype of these SNPs was associated with higher risk for type 2 diabetes with or without metabolic syndrome (P = 0.002, OR 2.2; P = 0.004, OR 3.1). These data suggest that HNF4 alpha SNPs and haplotypes contributed to increased type 2 diabetes risk in the Malaysian population.
    Matched MeSH terms: Genetic Association Studies
  20. Benjamin EJ, Muntner P, Alonso A, Bittencourt MS, Callaway CW, Carson AP, et al.
    Circulation, 2019 03 05;139(10):e56-e528.
    PMID: 30700139 DOI: 10.1161/CIR.0000000000000659
    Matched MeSH terms: American Heart Association
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