Displaying publications 1 - 20 of 406 in total

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  1. Prasankok P, Ota H, Toda M, Panha S
    Zoolog Sci, 2007 Feb;24(2):189-97.
    PMID: 17409732
    We examined allozyme variation in two camaenid tree snails, Amphidromus atricallosus and A. inversus, across two principal regions of Thailand and from Singapore, plus for A. inversus, one site in peninsular Malaysia. Using horizontal starch gel electrophoresis, 13 allozyme loci (11 polymorphic) were screened for A. atricallosus and 18 (5 polymorphic) for A. inversus. Heterozygosity was higher in A. atricallosus (Hexp=0.018-0.201, mean=0.085) than in A. inversus (Hexp=0-0.023, mean= 0.002). Genetic heterogeneity among samples was higher in A. inversus (Fst=0.965) than in A. atricallosus (Fst=0.781). Within A. atricallosus, populations were more differentiated in southern Thailand (Fst=0.551) than in eastern Thailand (Fst=0.144). The high Fst and low Hexp in populations of A. inversus suggest that this species is likely to have experienced a series of strong bottlenecks, perhaps occurring chiefly on offshore continental-shelf islands. The low Fst values of A. atricallosus in eastern Thailand suggest frequent gene flows among populations in this region. The southern and eastern samples of A. atricallosus exhibited fixed allele differences at four loci and great genetic distance (Nei's D=0.485-0.946), suggesting that these two samples may actually represent, or else be evolving into, separate species.
    Matched MeSH terms: Gene Frequency
  2. Tian S, Meng YH, Liu MY, Sun F, Chen JH, Du HL, et al.
    Zool Res, 2013 Apr;34(2):97-102.
    PMID: 23572358 DOI: 10.3724/SP.J.1141.2013.02097
    In most Old world monkey species, TRIM5α plays a role in combating retroviruses and restricting HIV-1. Alongside TRIM5α, the TRIMCyp fusion gene formed by the retrotransposition of a CypA pseudogene cDNA to 3' terminal or 3'-UTR of TRIM5 gene in these monkeys has become a key research area in anti HIV-1 factors. The regional differences, gene frequencies, genotypes, and retrovirus restrictive activities of TRIMCyp vary among different primate species. While the frequencies of cynomolgus TRIMCyp have been studied in several areas of Southeast Asia, the frequency and prevalence of cynomolgus TRIMCyp in China remains unclear. In this study, we screened 1, 594 cynomolgus samples from 11 monkey manufacturers located across 5 provinces in China. Our results showed that the frequencies of TRIMCyp range from 7.65% to 19.79%, markedly lower than the frequencies found in monkey species in the Philippines, Malaysia and Indonesia (ranging from 34.85% to 100%). We speculate that potentially the latter were isolated groups established since 1978. The NE haplotype frequencies of cynomolgus TRIMCyp were 4.93% in China, also significantly lower than those found in species in the Philippines, Malaysia and Indonesia (from 11.1% to 14.3%). Our research provides interesting findings that contribute towards a more firm basis of further studies of HIV-1 animal models and relevant pathogenesis.
    Matched MeSH terms: Gene Frequency*
  3. Wei W, Fang L, Wang N, Zhang T, Zeng JB, Lin MT
    PMID: 22875498 DOI: 10.3760/cma.j.issn.1003-9406.2012.04.009
    To investigate the frequency of CYP2C19 polymorphisms involved in clopidogrel metabolism in Fujian Han population.
    Matched MeSH terms: Gene Frequency
  4. Nurfadhlina M, Foong K, Teh LK, Tan SC, Mohd Zaki S, Ismail R
    Xenobiotica, 2006 Aug;36(8):684-92.
    PMID: 16891249
    The genetically polymorphic cytochrome P450 (CYP) 2A6 is the major nicotine-oxidase in humans that may contribute to nicotine dependence and cancer susceptibility. The authors investigated the types and frequencies of CYP2A6 alleles in the three major ethnic groups in Malaysia and CYP2A6*1A, CYP2A6*1B, CYP2A6*1x2, CYP2A6*2, CYP2A6*3, CYP2A6*4, CYP2A6*5, CYP2A6*7, CYP2A6*8 and CYP2A6*10 were determined by allele-specific polymerase chain reaction (PCR) in 270 Malays, 172 Chinese and 174 Indians. Except for CYP2A6*2 and *3 that were not detected in the Malays and Chinese, all the other alleles were detected. Frequencies for the CYP2A6*4 allele were 7, 5 and 2%, respectively, in Malays, Chinese and Indians. A statistically significant high frequency of the duplicated CYP2A6*1x2 allele occurred among Chinese. Among Malays and Chinese, the most common allele was CYP2A6*1B, but it was CYP2A6*1A among Indians. These ethnic difference in frequencies suggested that further studies are required to investigate the implications on diseases such as cancer and smoking behaviour among these major ethnic groups in Malaysia.
    Matched MeSH terms: Gene Frequency*
  5. Mustapha MA, Shahpudin SN, Aziz AA, Ankathil R
    World J Gastroenterol, 2012 Jun 7;18(21):2668-73.
    PMID: 22690076 DOI: 10.3748/wjg.v18.i21.2668
    To investigate the allele and genotype frequencies and associated risk of interleukin (IL)-8 -251T>A polymorphism on colorectal cancer (CRC) susceptibility risk.
    Matched MeSH terms: Gene Frequency
  6. Ahmad Aizat AA, Siti Nurfatimah MS, Aminudin MM, Ankathil R
    World J Gastroenterol, 2013 Jun 21;19(23):3623-8.
    PMID: 23801864 DOI: 10.3748/wjg.v19.i23.3623
    To investigate the risk association of xeroderma pigmentosum group C (XPC) Lys939Gln polymorphism alone and in combination with cigarette smoking on colorectal cancer (CRC) predisposition.
    Matched MeSH terms: Gene Frequency
  7. Maran S, Lee YY, Xu S, Rajab NS, Hasan N, Syed Abdul Aziz SH, et al.
    World J Gastroenterol, 2013 Jun 21;19(23):3615-22.
    PMID: 23801863 DOI: 10.3748/wjg.v19.i23.3615
    To identify genes associated with gastric precancerous lesions in Helicobacter pylori (H. pylori)-susceptible ethnic Malays.
    Matched MeSH terms: Gene Frequency
  8. Saha N, Banerjee B
    Vox Sang, 1973;24(6):542-4.
    PMID: 4722836
    Matched MeSH terms: Gene Frequency*
  9. Javanmard A, Azadzadeh N, Esmailizadeh AK
    Vet Res Commun, 2011 Mar;35(3):157-67.
    PMID: 21327517 DOI: 10.1007/s11259-011-9467-9
    The objective of this study was to investigate association between GDF9 and BMP15 gene polymorphism and litter size in fat-tailed sheep, a total of 97 mature ewes from four breeds (Afshari=19; Baluchi=18; Makui=30 and Mehraban=30) were genotyped for the BMP15 HinfI and GDF9 HhaI polymorphisms by PCR-RFLP technique. The highest and lowest mutant allele frequencies were found in Makui (0.27) and Afshari (0.10) sheep for the BMP15 gene and in Afshari (0.24) and Mehraban (0.18) sheep for the GDF9 gene, respectively. Litter size was significantly influenced by genotype of the ewe for two genes (P < 0.01). Heterozygous genotypes for both loci showed higher litter size than homozygous genotypes (P < 0.01). None of the individuals carried homozygous genotype for both of the GDF9 and BMP15 variants in these breeds. The individuals carrying the mutant allele for one of the investigated candidate gene still showed fertile phenotype. Thus, existence of homozygosity at one of the BMP15 and GDF9 variant is not probably able to block normal hormonal pathway of reproduction in fat-tailed sheep.
    Matched MeSH terms: Gene Frequency*
  10. Chan JY, Li H, Singh O, Mahajan A, Ramasamy S, Subramaniyan K, et al.
    Urol Oncol, 2013 Nov;31(8):1553-60.
    PMID: 22561070 DOI: 10.1016/j.urolonc.2012.02.009
    OBJECTIVES: Recently, several genome-wide association studies have demonstrated a cumulative association of 5 polymorphic variants in chromosomes 8q24 and 17q with prostate cancer (CaP) risk in Caucasians, particularly those harboring aggressive clinicopathologic characteristics. The purpose of this study was to evaluate the influence of these variants on CaP susceptibility in Singaporean Asian men.
    MATERIALS AND METHODS: We performed a case-control study in 289 Chinese CaP patients and 412 healthy subjects (144 Chinese, 134 Malays, and 134 Indians), and examined the association of the 5 single nucleotide polymorphisms (SNPs) with CaP.
    RESULTS: In the healthy subjects, rs16901979 A-allele frequency was highest amongst Chinese (0.32) compared with Malays (0.13; P < 0.0001) or Indians (0.09; P < 0.0001); rs6983267 G-allele was highest in Indians (0.51) compared with Chinese (0.42; P = 0.041) or Malays (0.43; P = 0.077); whereas rs1859962 G-allele frequency was highest amongst Indians (0.56) compared with Chinese (0.40; P = 0.0002) or Malays (0.38; P < 0.0001). Individuals with the rs4430796 TT genotype were at increased CaP risk in the Chinese via a recessive model (odds ratios (OR) = 1.56, 95% CI = 1.04-2.33). Significant associations were observed for rs4430796 TT with Gleason scores of ≥ 7 (OR = 1.76, 95% CI = 1.14-2.73) and prostate-specific antigen (PSA) levels of ≥ 10 ng/ml at diagnosis (OR = 1.63, 95% CI = 1.01-2.63), as well as for rs6983267 GG with stage 3-4 CaPs (OR = 1.91, 95% CI = 1.01-3.61). A cumulative gene interaction influence on disease risk, which approximately doubled for individuals with at least 2 susceptibility genotypes, was also identified (OR = 2.18, 95% CI = 1.10-4.32).
    CONCLUSIONS: This exploratory analysis suggests that the 5 genetic variants previously described may contribute to prostate cancer risk in Singaporean men.
    KEYWORDS: Cancer; Ethnicity; Gleason; Pharmacogenetics; Polymorphism; Prostate
    Matched MeSH terms: Gene Frequency
  11. Pang SC, Chiang LP, Tan CH, Vythilingam I, Lam-Phua SG, Ng LC
    Trop Biomed, 2015 Mar;32(1):140-50.
    PMID: 25801264 MyJurnal
    There has been a worldwide surge in the number and severity of dengue in the past decades. In Singapore, relentless vector control efforts have been put in to control the disease since the 1960's. Space spraying, fogging, chemical treatment and source reduction are some commonly used methodologies for controlling its vectors, particularly Aedes aegypti. Here, as we explored the use of a commercially available delthamethrin-treated net as an alternative strategy and the efficacy of the treated net was found to be limited. Through bioassays and molecular studies, the failure of the treated net to render high mortality rate was found to be associated with the knockdown resistance (kdr) mutation. This is the first report of kdr- mutations in Singapore's Ae. aegypti. At least one point mutation, either homozygous or heterozygous, at amino acid residue V1016G of DIIS6 or F1269C of DIIIS6 was detected in 93% of field strains of Ae. aegypti. Various permutations of wild type and mutant amino acids of the four alleles were found to result in varying degree of survival rate among local field Ae. aegypti when exposed to the deltamethrin treated net. Together with the association of higher survival rate with the presence of both V1016G and F1269C, the data suggest the role of these mutations in the resistance to the deltamethrin. The high prevalence of these mutations were confirmed in a country wide survey where 70% and 72% of the 201 Ae. aegypti analysed possessed the mutations at residues 1016 and 1269 respectively. The highest mutated frequency combination was found to be heterozygous alleles (VG/FC) at both residues 1016 and 1269 (37.8%), followed by homozygous mutation at allele 1269 (24.4%) and homozygous mutation at allele 1016 (22.9%). The kdr- type of resistance among the vector is likely to undermine the effectiveness of pyrethroids treated materials against these mosquitoes.
    Matched MeSH terms: Gene Frequency
  12. Krishnan PB, Abdullah M, Hudu SA, Sekawi Z, Tan SS, Amin-Nordin S
    Trop Biomed, 2019 Sep 01;36(3):703-708.
    PMID: 33597492
    Asian countries account for almost three quarter of hepatocellular carcinoma (HCC) reported globally and chronic hepatitis B infection is one of the main contributors. Clinical observations show that Malay patients with chronic hepatitis B and HCC tend to have a worse outcome, when compared to other two major races in Malaysia. The objectives of this study was to determine the frequency of human leukocyte antigen (HLA) class II alleles in chronic hepatitis B patients with HCC among Malays compared to the general population to identify potential associations of HLA alleles with this disease. HLA class II typing was performed in chronic hepatitis B patients with hepatocellular carcinoma (n=12) by -polymerase chain reaction, sequence specific primer (PCR-SSP) method. There were higher allelic frequencies of certain HLA-DQB1 and HLA-DRB1 alleles; HLA-DQB1*03 (07) (41.7%), and HLA-DRB1*12 (41.7% vs 28.6%) and compared to controls (41.7% vs 29.7%). However, there was no significant statistical correlation found when compared with the normal healthy general population. This study provides an insight into the HLA Class II association with chronic hepatitis B and hepatocellular carcinoma in Malays. However, findings from this study should be validated with a larger number of samples using a high resolution HLA typing.
    Matched MeSH terms: Gene Frequency
  13. George E, Khuziah R
    Trop Geogr Med, 1984 Jun;36(2):123-5.
    PMID: 6332395
    Hereditary haemolytic anaemias have been found to be a significant cause of haemolytic disease in West Malaysia. This paper reports a micromapping study of 916 healthy Malay males from June to August 1983 to determine the distribution of the relevant thalassaemia genes in West Malaysia. Beta thalassaemia trait was found in 2.18%, HbE 3.49% and alpha thal2 (alpha+) trait in 26%. Of the sixteen transfusion dependant Malay thalassaemic patients at the Paediatric Unit, National University of Malaysia, eight patients had HbE beta thalassaemia and the rest are beta thalassaemia major; these patients who are transfusion dependant receive inadequate treatment. Prevention is the only resort.
    Matched MeSH terms: Gene Frequency
  14. Liu C, Kanazawa T, Tian Y, Mohamed Saini S, Mancuso S, Mostaid MS, et al.
    Transl Psychiatry, 2019 08 27;9(1):205.
    PMID: 31455759 DOI: 10.1038/s41398-019-0532-4
    Over 3000 candidate gene association studies have been performed to elucidate the genetic underpinnings of schizophrenia. However, a comprehensive evaluation of these studies' findings has not been undertaken since the decommissioning of the schizophrenia gene (SzGene) database in 2011. As such, we systematically identified and carried out random-effects meta-analyses for all polymorphisms with four or more independent studies in schizophrenia along with a series of expanded meta-analyses incorporating published and unpublished genome-wide association (GWA) study data. Based on 550 meta-analyses, 11 SNPs in eight linkage disequilibrium (LD) independent loci showed Bonferroni-significant associations with schizophrenia. Expanded meta-analyses identified an additional 10 SNPs, for a total of 21 Bonferroni-significant SNPs in 14 LD-independent loci. Three of these loci (MTHFR, DAOA, ARVCF) had never been implicated by a schizophrenia GWA study. In sum, the present study has provided a comprehensive summary of the current schizophrenia genetics knowledgebase and has made available all the collected data as a resource for the research community.
    Matched MeSH terms: Gene Frequency
  15. Saini SM, Mancuso SG, Mostaid MS, Liu C, Pantelis C, Everall IP, et al.
    Transl Psychiatry, 2017 Aug 08;7(8):e1196.
    PMID: 28786982 DOI: 10.1038/tp.2017.172
    Genome-wide association study (GWAS) evidence has identified the metabotropic glutamate receptor 3 (GRM3) gene as a potential harbor for schizophrenia risk variants. However, previous meta-analyses have refuted the association between GRM3 single-nucleotide polymorphisms (SNPs) and schizophrenia risk. To reconcile these conflicting findings, we conducted the largest and most comprehensive meta-analysis of 14 SNPs in GRM3 from a total of 11 318 schizophrenia cases, 13 820 controls and 486 parent-proband trios. We found significant associations for three SNPs (rs2237562: odds ratio (OR)=1.06, 95% confidence interval (CI)=1.02-1.11, P=0.017; rs13242038: OR=0.90, 95% CI=0.85-0.96, P=0.016 and rs917071: OR=0.94, 95% CI=0.91-0.97, P=0.003). Two of these SNPs (rs2237562, rs917071) were in strong-to-moderate linkage disequilibrium with the top GRM3 GWAS significant SNP (rs12704290) reported by the Schizophrenia Working Group of the Psychiatric Genomics Consortium. We also found evidence for population stratification related to rs2237562 in that the 'risk' allele was dependent on the population under study. Our findings support the GWAS-implicated link between GRM3 genetic variation and schizophrenia risk as well as the notion that alleles conferring this risk may be population specific.
    Matched MeSH terms: Gene Frequency
  16. Hajar CGN, Zulkafli Z, Md Riffin NS, Tuan Mohammad TH, Safuan S, Nelson BR, et al.
    Transfus Apher Sci, 2020 Apr;59(2):102651.
    PMID: 31606336 DOI: 10.1016/j.transci.2019.09.004
    BACKGROUND: Human neutrophil antigens (HNAs) are implicated in several clinical disorders and their allelic variations have been reported for many populations. This new study was aimed to report the genotype and alleles frequencies of HNA-1, -3, -4 and -5 loci in Malays, Chinese and Indians in Peninsular Malaysia.

    METHODS: A total of 222 blood samples were collected from healthy, unrelated Malay, Chinese and Indian individuals. Their HNA-1, -3 and -4 and HNA-5 loci were genotyped using polymerase chain reaction-sequence specific primer (PCR-SSP) or PCR-restriction fragment length polymorphism (RFLP) assays.

    RESULTS: All HNA loci are polymorphic, except for HNA -4. Geneotypes HNA-1a/1b, -3a/3b and -4a/4a were observed most frequently at these three loci in all three ethnic groups. In contrast, HNA-5a/5b and -5a/5a were observed as the predominant genotypes in Malays vs. Chinese and Indians, respectively. The Malays, Chinese and Indians shared HNA -3a (0.505-0.527), HNA -4a (1.000) and -5a (0.676-0.854) as the most frequent alleles. However, HNA-1a was found to be the most common in Malays (0.506) and Chinese (0.504) and HNA-1b for Indians (0.525).

    CONCLUSION: Combined with HNA data that have been published for Malay subethnic and Orang Asli groups, this study provides the first fully comprehensive HNA dataset for populations to be found in Peninsular Malaysia. Overall, our findings provide further evidence of genetic complexity in the region. This now publicly available HNA dataset can be used as a reliable reference source for improving medical outcomes.

    Matched MeSH terms: Gene Frequency/immunology*
  17. Yusof W, Hua GS
    Toxicol. Mech. Methods, 2012 Apr;22(3):184-92.
    PMID: 22003869 DOI: 10.3109/15376516.2011.623331
    Artesunate (AS) and amodiaquine (AQ) are two prodrugs widely used as antimalarial agents and are metabolized by the CYP P450 2A6 (CYP 2A6) and CYP P450 2C8 (CYP 2C8) enzymes, respectively.
    Matched MeSH terms: Gene Frequency
  18. Jinam TA, Saitou N, Edo J, Mahmood A, Phipps ME
    Tissue Antigens, 2010 Feb;75(2):151-8.
    PMID: 20003135 DOI: 10.1111/j.1399-0039.2009.01417.x
    This is the first report of high-resolution human leukocyte antigen (HLA) typing in four indigenous groups in Malaysia. A total of 99 normal, healthy participants representing the Negrito (Jehai and Kensiu), Proto-Malay (Temuan) and a native group of Borneo (Bidayuh) were typed for HLA-A, -B, -DRB1 and -DQB1 genes using sequence-based typing. Eleven HLA-A, 26 HLA-B, 16 HLA-DRB1 and 14 HLA-DQB1 alleles were detected, including a new allele, HLA-B*3589 in the Jehai. Highly frequent alleles were A*2407, B*1513, B*1801, DRB1*0901, DRB1*1202, DRB1*1502, DQB1*0303 and DQB1*0502. Principal component analysis based on high-resolution HLA-A, -B and -DRB1 allele frequencies showed close affinities among all four groups, including the Negritos, with other Southeast Asian populations. These results showed the scope of HLA diversity in these indigenous minority groups and may prove beneficial for future disease association, anthropological and forensic studies.
    Matched MeSH terms: Gene Frequency
  19. Dunn DS, Choy MK, Phipps ME, Kulski JK
    Tissue Antigens, 2007 Aug;70(2):136-43.
    PMID: 17610418
    The frequency and association of polymorphic Alu insertions (POALINs) with human leucocyte antigen (HLA) class I genes within the class I genomic region of the major histocompatibility complex (MHC) have been reported previously for three populations: the Australian Caucasian, Japanese and north-eastern Thai populations. Here, we report on the individual insertion frequency of the five POALINs within the MHC class I region, their HLA-A and HLA-B associations, the POALIN haplotype frequencies and the HLA-A/POALIN four-loci haplotype frequencies in the Malaysian Chinese population. The phylogenetic relationship of the four populations based on the five POALIN allele frequencies was also examined. In the Malaysian Chinese population, the POALIN AluyHG was present at the highest frequency (0.560), followed by AluyHJ (0.300), AluyMICB (0.170), AluyTF (0.040) and AluyHF (0.030). The most frequent five-loci POALIN haplotype of the 16 inferred haplotypes was the AluyHG single insertion haplotype at a frequency of 0.489. Strong associations were present between AluyHJ and HLA-A24, HLA-A33 and HLA-A11 and between AluyHG and HLA-A2, HLA-A24 and HLA-A11, and these were reflected by the inferred haplotype frequencies constructed from the combination of the HLA-A locus and the AluyHG, AluyHJ and AluyHF loci. The strongest association of AluyMICB was with the HLA-B54 allele (five of five), whereas the associations with the other 17 HLA-B alleles were weak, moderate or undetermined. Phylogenetic analysis of the five POALIN allele frequencies places the Malaysian Chinese closest to the Japanese and north-eastern Thai populations in the same cluster and separate to the Australian Caucasian population. The MHC POALINs are confirmed in this study to be informative genetic markers in lineage (haplotype) analysis, population genetics and evolutionary relationships, especially in studying the MHC genomic region.
    Matched MeSH terms: Gene Frequency
  20. Hou L, Tu B, Ling G, Tang T, Cao K, Steiner NK, et al.
    Tissue Antigens, 2006 Jan;67(1):66-9.
    PMID: 16451205
    Strategies to resolve B*18 alleles which carry a deletion in intron 1 close to the 5' end of exon 2 relative to other HLA-B alleles or a null allele mutation in exon 1 and to resolve ambiguities among allele combinations including B*18 are described. B*18 allele frequencies from volunteer donors recruited for two hematopoietic stem cell registries show the presence of two alleles, B*180101 and B*1802, in a population from Singapore and only B*180101 in African-Americans.
    Matched MeSH terms: Gene Frequency*
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