MyMedR

Clinical relevance of VKORC1 (G-1639A and C1173T) and CYP2C9*3 among patients on warfarin

Teh LK, Langmia IM, Fazleen Haslinda MH, Ngow HA, Roziah MJ, Harun R, et al.

J Clin Pharm Ther, 2012 Apr;37(2):232-6.

PMID: 21507031 DOI: 10.1111/j.1365-2710.2011.01262.x

Testing for cytochrome P450-2C9 (CYP2C9) and vitamin K epoxide reductase complex subunit 1 (VKORC1) variant alleles is recommended by the FDA for dosing of warfarin. However, dose prediction models derived from data obtained in one population may not be applicable to another. We therefore studied the impact of genetic polymorphisms of CYP2C9 and VKORC1 on warfarin dose requirement in Malaysia.

Matched MeSH terms: Polymorphism, Genetic

Pharmacogenomics of CYP2D6: molecular genetics, interethnic differences and clinical importance

Teh LK, Bertilsson L

Drug Metab. Pharmacokinet., 2012;27(1):55-67.

PMID: 22185816

CYP2D6 has received intense attention since the beginning of the pharmacogenetic era in the 1970s. This is because of its involvement in the metabolism of more than 25% of the marketed drugs, the large geographical and inter-ethnic differences in the genetic polymorphism and possible drug-induced toxicity. Many interesting reviews have been published on CYP2D6 and this review aims to reinstate the importance of the genetic polymorphism of CYP2D6 in different populations as well as some clinical implications and important drug interactions.

Matched MeSH terms: Polymorphism, Genetic*

Tridimensional personalities and polymorphism of dopamine D2 receptor among heroin addicts

Teh LK, Izuddin AF, M H FH, Zakaria ZA, Salleh MZ

Biol Res Nurs, 2012 Apr;14(2):188-96.

PMID: 21613340 DOI: 10.1177/1099800411405030

Drug addiction is a multifactorial disorder. Researchers have posited that an individual's inherited behavioral propensity or temperament contributes to the disorder by shaping a personality strongly linked with the risk of drug abuse. Further, they hypothesize that the polymorphism of dopamine D2 receptor increases the susceptibility to and severity of addiction. We, therefore, investigated possible associations between dopamine D2 receptor (DRD2) and personality traits among intravenous heroin addicts.

Matched MeSH terms: Polymorphism, Genetic*

Single step PCR for detection of allelic variation of MDR1 gene (P-glycoprotein) among three ethnic groups in Malaysia

Teh LK, Lee WL, Amir J, Salleh MZ, Ismail R

J Clin Pharm Ther, 2007 Jun;32(3):313-9.

PMID: 17489883

P-glycoprotein (PgP) is the most extensively studied ATP-binding cassette (ABC) coded by MDR1 gene. To date, 29 single nucleotide polymorphisms (SNPs) have been identified; but only SNP C3435T has been correlated with intestinal PgP expression levels and shown to influence the absorption of orally taken drugs that are PgP substrates. Individuals homozygous for the T allele have more than fourfold lower PgP expression compared with C/C individuals. We developed a one step primer based allele specific PCR method to detect SNP at C3435T to investigate the distribution of this genotype in the local population.

Matched MeSH terms: Polymorphism, Genetic*

Genetic polymorphism of CYP2D6 in patients with cardiovascular disease -- a cohort study

Teh LK, Zilfalil BA, Marina I, Rosemi BS, Ismail R

J Clin Pharm Ther, 2004 Dec;29(6):559-64.

PMID: 15584944 DOI: 10.1111/j.1365-2710.2004.00600.x

BACKGROUND: Cardiovascular diseases are complex diseases that are influenced by both environmental and genetic factors. CYP2D6 found in the brain and the heart is involved in the metabolism of many environmental and some endogenous substances and neurotransmitters responsible for maintaining homeostasis. This raises an interesting hypothesis that it may have a role in the development of or protection against cardiovascular diseases.
OBJECTIVE: To study the distribution of genotypes of CYP2D6 among patients with cardiovascular diseases in Malaysia.
METHOD:We obtained DNA from 128 patients who were followed up for cardiovascular diseases. Polymerase chain reaction-based methods were used to determine common CYP2D6 alleles.
RESULTS: One hundred and twenty-eight patients were enrolled. Most of the patients also had concurrent illnesses. Eleven genotypes were identified in the patients and 41% carried CYP2D6*1/*10. The second most common genotype was homozygous for the wild type gene, followed by homozygous CYP2D6*10/*10 at 14.48 %. A small percentage of the patients were heterozygous CYP2D6*1/*4. One patient was genotyped homozygous CYP2D6*4/*4 predicting a poor metabolizer prevalence of 0.78% (95% CI +/- 1.52%). Analysis using Hardy-Weinberg equilibrium showed that all of the gnotypes were consistent with equilibrium except for CYP2D6*1/*10 (chi(2); P < 0.05).
CONCLUSION: Our study suggests a possible involvement of CYP2D6 genotypes in cardiovascular system diseases, which need to be validated by further studies.

Matched MeSH terms: Polymorphism, Genetic

Heterogeneity of the CYP2D6 gene among Malays in Malaysia

Teh LK, Ismail R, Yusoff R, Hussein A, Isa MN, Rahman AR

J Clin Pharm Ther, 2001 Jun;26(3):205-11.

PMID: 11422605

Although Malays shared an origin with Chinese, their evolution saw substantial divergences. Phenotyping studies suggested that they differed in CYP2D6 polymorphism, with higher PM prevalence but lesser right-shift for debrisoquine MRs.

Matched MeSH terms: Polymorphism, Genetic

Potential of dihydropyrimidine dehydrogenase genotypes in personalizing 5-fluorouracil therapy among colorectal cancer patients

Teh LK, Hamzah S, Hashim H, Bannur Z, Zakaria ZA, Hasbullani Z, et al.

Ther Drug Monit, 2013 Oct;35(5):624-30.

PMID: 23942539 DOI: 10.1097/FTD.0b013e318290acd2

Dihydropyrimidine dehydrogenase (DPD) is a pyrimidine catabolic enzyme involved in the initial and rate-limiting step of the catabolic pathway of toxic metabolites of 5-fluorouracil (5-FU). Several studies have reported that deficiency of DPD and polymorphisms of its gene are related to 5-FU toxicities and death. Association between serum concentration of 5-FU and its related toxicity has also been previously demonstrated. Hence, this study aims to understand the role of DPYD variants in serum level of 5-FU and the risk of developing toxicity to prevent adverse reactions and maximize therapy outcome for personalized medicine.

Matched MeSH terms: Polymorphism, Genetic/genetics

Polymorphisms of UGT1A1*6, UGT1A1*27 & UGT1A1*28 in three major ethnic groups from Malaysia

Teh LK, Hashim H, Zakaria ZA, Salleh MZ

Indian J Med Res, 2012 Aug;136(2):249-59.

PMID: 22960892

Genetic polymorphisms of uridine diphosphate glucuronyltransferase 1A1 (UGT1A1) have been associated with a wide variation of responses among patients prescribed with irinotecan. Lack of this enzyme is known to be associated with a high incidence of severe toxicity. The objective of this study was to investigate the prevalence of three different variants of UGT1A1 (UGT1A1*6, UGT1A1*27 and UGT1A1*28), which are associated with reduced enzyme activity and increased irinotecan toxicity, in the three main ethnic groups in Malaysia (Malays, Chinese and Indians).

Matched MeSH terms: Polymorphism, Genetic

Multiple endocrine neoplasia type 1 (MEN1) in two Asian families

Teh BT, Hii SI, David R, Parameswaran V, Grimmond S, Walters MK, et al.

Hum Genet, 1994 Nov;94(5):468-72.

PMID: 7959678 DOI: 10.1007/bf00211009

Multiple endocrine neoplasia type 1 (MEN1), an autosomal dominant disease characterized by neoplasia of the parathyroid glands, anterior pituitary and endocrine pancreas, is rarely reported in Asian populations. The MEN1 gene, mapped to chromosome 11q13 but yet to be cloned, has been found to be homogeneous in Caucasian populations through linkage analysis. Here, two previously unreported Asian kindreds with MEN1 are described; linkage analysis using microsatellite polymorphic markers in the MEN1 region was carried out. The first kindred, of Mongolian-Chinese origin, is a multigeneration family with over 150 living members, eight of whom are affected to date. The second kindred is of Chinese origin consisting of four affected members. Linkage to chromosome 11q13 was confirmed in both kindreds, supporting evidence for genetic homogeneity. A recombination in the larger kindred localizes the gene distal to marker D11S956, consistent with its placement from previous studies. We also show that it is feasible to use these markers for predictive testing, as four gene carriers were detected in 13 family members with unknown disease status in the first kindred.

Matched MeSH terms: Polymorphism, Genetic

Genetic Association Analysis of Dopamine DRD3 Ser9Gly Polymorphism and Schizophrenia in Malay Population

Tee S, Tang P, Loh H

Iran J Public Health, 2011;40(2):6-10.

PMID: 23113067

BACKGROUND: Molecular components of the dopamine receptor (DRD3) play an important role in the pathophysiology of schizophrenia (SCZ). Previous studies have demonstrated an association between the DRD3 Ser9Gly polymorphism and SCZ but the results have been inconclusive.

METHOD: In this study, we investigated this controversial association between the Ser9Gly (A/G) polymorphism and SCZ using Malay cases-control (261 cases/157 controls) samples. PCR-RFLP was performed to genotype the distribution of the DRD3 Ser9Gly polymorphism.

RESULTS: Both healthy control and SCHZ patient groups were in of Hardy-Weinberg equilibrium for the analyzed genetic variability. There was a significant association between the genotype distribution DRD3 polymorphisms and SCZ (χ(2)= 9.359; df = 2; P = 0.009).

CONCLUSION: We believe that further studies are required to examine the association between others dopamine-related genes and the behavioral phenotypes of SCZ.

Matched MeSH terms: Polymorphism, Genetic

Autosomal STR polymorphism in Sikh population of Peninsular Malaysia

Teck TC, Kook SC, Badruddin N, Panneerchelvam S, Norazmi MN

J Forensic Sci, 2005 Sep;50(5):1223-4.

PMID: 16225236 DOI: 10.1520/JFS2005156

Matched MeSH terms: Polymorphism, Genetic*

Sequence analysis of the hypervariable regions of the 56 kDa immunodominant protein genes of Orientia tsutsugamushi strains in Malaysia

Tay ST, Rohani YM, Ho TM, Shamala D

Microbiol. Immunol., 2005;49(1):67-71.

PMID: 15665455

The DNA sequences encompassing two hypervariable regions, VD II and III of the 56 kDa immunodominant protein gene of 21 Malaysian strains of Orientia tsutsugamushi were determined. Two strains demonstrated a 100% DNA homology with the Gilliam prototype strain, and one with TH1817 strain and TA678 strain respectively. High percentages of DNA similarity (95-99%) were observed with Karp (4 strains), Gilliam (2 strains), TH1817 (4 strains), TC586 (3 strains) and TA763 (1 strain). The remaining strains demonstrated the highest DNA similarity with TA763 (1 strain, 89%), TA678 (1 strain, 86%) and TA686 (1 strain, 87%). Our study provides additional evidence on the existence and the genetic heterogeneity of TA strains of the Southeast Asia and their closely related strains in Malaysia.

Matched MeSH terms: Polymorphism, Genetic

Fulltext Sequence polymorphism and PCR-restriction fragment length polymorphism analysis of the flagellin gene of Burkholderia pseudomallei

Tay ST, Cheah PC, Puthucheary SD

J Clin Microbiol, 2010 Apr;48(4):1465-7.

PMID: 20089759 DOI: 10.1128/JCM.01131-09

Four flagellin allelic types (I to IV) of Burkholderia pseudomallei were identified based on their sequence variation and restriction fragment length polymorphism (RFLP) analysis of the amplified flagellin gene. Flagellin allelic type I was the most predominantly (75.0%) found among the 100 clinical isolates of B. pseudomallei investigated in this study.

Matched MeSH terms: Polymorphism, Genetic*

Fulltext Population structure of Helicobacter pylori among ethnic groups in Malaysia: recent acquisition of the bacterium by the Malay population

Tay CY, Mitchell H, Dong Q, Goh KL, Dawes IW, Lan R

BMC Microbiol, 2009;9:126.

PMID: 19538757 DOI: 10.1186/1471-2180-9-126

Helicobacter pylori is a major gastric bacterial pathogen. This pathogen has been shown to follow the routes of human migration by their geographical origin and currently the global H. pylori population has been divided into six ancestral populations, three from Africa, two from Asia and one from Europe. Malaysia is made up of three major ethnic populations, Malay, Chinese and Indian, providing a good population for studying recent H. pylori migration and admixture.

Matched MeSH terms: Polymorphism, Genetic

Genetic polymorphism of the vitamin D-binding protein (DBP) in crab-eating macaques (Macaca fascicularis)

Tanaka H, Kawamoto Y, Terao K

J Med Primatol, 1991 May;20(3):126-32.

PMID: 1895332

Vitamin D-binding protein (DBP) of crab-eating macaques (Macaca fascicularis) was examined by means of three electrophoretic methods. DBP phenotypes were observed to be one or two bands in each method. All of DBP molecular variants could be detected by the simultaneous typing with these three methods. Family analysis suggested that DBP variants followed the mode of autosomal codominant inheritance. A total of 17 phenotypes governed by at least 11 alleles were observed in the populations of Malaysia, Indonesia, and the Philippines. The genetic variability was high in Malaysian and Indonesian populations but low in the Philippine population.

Matched MeSH terms: Polymorphism, Genetic*

An efficient Method for single locus microsatellite marker development

Tan, Soon Guan

Buletin Persatuan Genetik Malaysia, 2002;8(1):0-0.

MyJurnal

In various biological studies, for example those in population genetics, conservation biology, forensic science, gene mapping, breed, strain and population characterization and identification, marker assisted selection and the identification of cryptic species complexes, codominant genetic markers play important roles. The information that can be gained from them are far superior than those from dominant markers like random amplified polymorphic DNA (RAPD), amplified fragment length polymorphisms (AFLP), direct amplification of length polymorphisms (DALP) and randomly amplified microsatellites (RAM) or inter simple sequence repeats (ISSR).

Matched MeSH terms: Polymorphism, Genetic

Genetic variability of Blastocystis sp. isolates obtained from cancer and HIV/AIDS patients

Tan TC, Ong SC, Suresh KG

Parasitol Res, 2009 Oct;105(5):1283-6.

PMID: 19603182 DOI: 10.1007/s00436-009-1551-5

This represents the first study to determine the genetic diversity of Blastocystis sp. among cancer and HIV/AIDS patients. Forty Blastocystis sp. isolates obtained from 20 cancer and 20 HIV/AIDS patients were genotyped by PCR using seven pairs of known sequenced-tagged site primers. Out of the 40 isolates, 38 were identified as one of the known genotypes and two isolates were negative with all the STS primers. Blastocystis sp. subtype 3 which is reported to be associated with disease was found to be predominant among the study subjects.

Matched MeSH terms: Polymorphism, Genetic*

FcgammaRIIa polymorphism in systemic lupus erythematosus

Tan SY

Kidney Blood Press Res, 2000;23(2):138-42.

PMID: 10765117 DOI: 10.1159/000025967

FcgammaRIIs are the most widely distributed of the Fcgamma receptor family and play an important role in the clearance of immune complexes. Evidence that the FcgammaRIIa-R131 allotype is less able to process and clear immune complexes effectively suggests that this may be a disease susceptibility factor for systemic lupus erythematosus (SLE). Data from studies published thus far do not agree on the potential role of FcgammaRIIa polymorphism in the genetics of SLE. Most studies in fact show no evidence for any correlation between polymorphism of FcgammaRIIa and risk for SLE. However, it remains to be determined whether FcgammaRIIa polymorphism may play a critical role in certain groups of patients, especially in those of differing ethnic background. Polymorphism of FcgammaRIIa may also be important in determining disease phenotype, and identification of this influence may have important implications in patient care and in identifying patients for more aggressive therapy.

Matched MeSH terms: Polymorphism, Genetic/genetics*

Association of CYP2C19*2 polymorphism with clopidogrel response and 1-year major adverse cardiovascular events in a multiethnic population with drug-eluting stents

Tan SSN, Fong AYY, Mejin M, Gerunsin J, Kong KL, Chin FYY, et al.

Pharmacogenomics, 2017 08;18(13):1225-1239.

PMID: 28745576 DOI: 10.2217/pgs-2017-0078

BACKGROUND: Patients undergoing elective percutaneous coronary intervention (PCI) with drug-eluting stents (DES) who have impaired clopidogrel response, have a higher risk of subsequent major adverse cardiovascular events (MACE).

AIM OF THE STUDY: To establish the relationship between CYP2C19 genotype, clopidogrel responsiveness and 1-year MACE.

MATERIALS & METHODS: Aspirin/clopidogrel responses were assessed with Multiplate Analyzer and CYP2C19*2 allele by SpartanRx.

RESULTS: A total of 42.0% carried ≥1 CYP2C19*2 allele. Prevalences of aspirin and clopidogrel high on-treatment platelet reactivity (HPR; local cutoffs: 300 AU*min for aspirin and 600 AU*min for clopidogrel) were 11.5% and 19.8% respectively. In multivariate ana-lysis, clopidogrel HPR was found to be an independent predictor for 1-year MACE (adj HR: 3.48, p = 0.022 ).

CONCLUSION: Having clopidogrel HPR could be a potentially modifiable risk factor guided by phenotyping.

Matched MeSH terms: Polymorphism, Genetic/genetics*

Transferrin C subtyping in Malaysians and in Indonesians from North Sumatra

Tan SG, Gan YY, Asuan K

Hum Genet, 1982;60(4):369-70.

PMID: 7106773

Malays, Chinese, and Indians from Peninsular Malaysia; Ibans and Bidayuh from Sarawak State; Kadazans from Sabah State, Northern Borneo; and Bataks, Minangkabau, and Javanese from North Sumatra, Indonesia, were subtyped for transferrin C by polyacrylamide gel isoelectric focusing. All nine populations studied are polymorphic for two alleles, TfCl and TfC2, TfC3 was polymorphic in six populations and present as a rare variant in the other three. The frequency of TfC1 ranged from 0.855 in Bidayuh to 0.711 in Javanese, that of TfC2 from 0.231 in Indians to 0.113 in Bidayuh, and that of TfC3 from 0.030 in Javanese and Chinese to 0.008 in Bidayuh. TfDchi is polymorphic in all the populations that we studied except in Minangkabau, in whom it is present as a rare variant, and in Indians, in whom it is absent.

Matched MeSH terms: Polymorphism, Genetic*

Displaying publications 81 - 100 of 441 in total