Displaying publications 81 - 100 of 135 in total

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  1. Baharin MF, Kader Ibrahim SB, Yap SH, Abdul Manaf AM, Mat Ripen A, Dhaliwal JS
    Malays J Pathol, 2015 Aug;37(2):153-8.
    PMID: 26277674 MyJurnal
    The Wiskott-Aldrich Syndrome (WAS) is an X-linked immunodeficiency condition characterized by microthrombocytopenia, eczema and recurrent infections. It is caused by mutations in the Wiskott-Aldrich Syndrome protein (WASP) gene. We investigated two Malay boys who presented with congenital thrombocytopenia, eczema and recurrent infections. Here we report two cases of WASP mutation in Malaysia from two unrelated families. One had a novel missense mutation in exon 1 while the other had a nonsense mutation in exon 2. Both patients succumbed to diseaserelated complications. A differential diagnosis of WAS should be considered in any male child who present with early onset thrombocytopenia, especially when this is associated with eczema and recurrent infections.
    Matched MeSH terms: DNA Mutational Analysis
  2. Tan JA, George E, Tan KL, Chow T, Tan PC, Hassan J, et al.
    Clin Exp Med, 2004 Dec;4(3):142-7.
    PMID: 15599663 DOI: 10.1007/s10238-004-0048-x
    Beta-thalassemia is the most-common genetic disorder of hemoglobin synthesis in Malaysia, and about 4.5% of the population are heterozygous carriers of the disorder. Prenatal diagnosis was performed for 96 couples using the Amplification Refractory Mutation System and Gap-Polymerase Chain Reaction. We identified 17 beta-globin defects-initiation codon for translation (T-G), -29 (A-G), -28 (A-G), CAP +1 (A-C), CD 8/9 (+G), CD 15 (G-A), CD 17 (A-T), CD 19 (A-G), Hb E (G-A), IVS1-1 (G-T), IVS1-5 (G-C), CD 41/42 (-CTTT), CD 71-72 (+A), IVS2-654 (CT), poly A(A-G), 100-kb Ggamma(Agammadeltabeta) degrees and 45-kb Filipino deletions. The 192 beta-alleles studied comprised Chinese (151 patients), Malay (21), Orang Asli from East Malaysia (15), Filipino (1), Indian (1), Indonesian Chinese (2), and Thai (1). In the Chinese, 2 beta-globin defects at CD 41/42 and IVS2-654 were responsible for 74% of beta-thalassemia. beta-mutations at CD 19, IVS1-1 (G-T), IVS1-5, poly A, and hemoglobin E caused 76% of the hemoglobin disorders in the Malays. The Filipino 45-kb deletion caused 73.3% of bthalassemia in the Orang Asli. Using genomic sequencing, the rare Chinese beta-mutation at CD 43 (G-T) was confirmed in 2 Chinese, and the Mediterranean mutation IVS1-1 (G-A) was observed in a Malay beta-thalassemia carrier. The beta-globin mutations confirmed in this prenatal diagnosis study were heterogenous and 65 (68%) couples showed a different globin defect from each other. The use of specific molecular protocols has allowed rapid and successful prenatal diagnosis of beta-thalassemia in Malaysia.
    Matched MeSH terms: DNA Mutational Analysis
  3. Xu A, Lin Y, Sheng H, Cheng J, Mei H, Ting TH, et al.
    Pediatr Diabetes, 2020 05;21(3):431-440.
    PMID: 31957151 DOI: 10.1111/pedi.12985
    OBJECTIVE: The purpose of this study was to investigate the molecular basis of maturity-onset diabetes of the young (MODY) by whole-exome sequencing (WES) and estimate the frequency and describe the clinical characteristics of MODY in southern China.

    METHODS: Genetic analysis was performed in 42 patients with MODY aged 1 month to 18 years among a cohort of 759 patients with diabetes, identified with the following four clinical criteria: age of diagnosis ≤18 years; negative pancreatic autoantibodies; family history of diabetes; or persistently detectable C-peptide; or diabetes associated with extrapancreatic features. GCK gene mutations were first screened by Sanger sequencing. GCK mutation-negative patients were further analyzed by WES.

    RESULTS: Mutations were identified in 24 patients: 20 mutations in GCK, 1 in HNF4A, 1 in INS, 1 in ABCC8, and a 17q12 microdeletion. Four previously unpublished novel GCK mutations: c.1108G>C in exon 9, and c.1339C>T, c.1288_1290delCTG, and c.1340_1343delGGGGinsCTGGTCT in exon 10 were detected. WES identified a novel missense mutation c.311A>G in exon 3 in the INS gene, and copy number variation analysis detected a 1.4 Mb microdeletion in the long arm of the chromosome 17q12 region. Compared with mutation-negative subjects, the mutation-positive subjects had lower hemoglobin A1c and initial blood glucose levels.

    CONCLUSIONS: Most MODY cases in this study were due to GCK mutations, which is in contrast to previous reports in Chinese patients. Diabetes associated with extrapancreatic features should be a clinical criterion for MODY genetic analysis. Mutational analysis by WES provided a precise diagnosis of MODY subtypes. Moreover, WES can be useful for detecting large deletions in coding regions in addition to point mutations.

    Matched MeSH terms: DNA Mutational Analysis
  4. Abdullah JM, Ahmad F, Ahmad KA, Ghazali MM, Jaafar H, Ideris A, et al.
    Neurol Res, 2007 Apr;29(3):239-42.
    PMID: 17509221
    Brain tumorigenesis is a complex process involving multiple genetic alterations. Cyclin D1 and BAX genes are two of the most important regulators in controlling the normal proliferation and apoptosis of cells, respectively. In this study, we analysed the possibilities of involvement of cyclin D1 and BAX genes in the gliomagenesis.
    Matched MeSH terms: DNA Mutational Analysis/methods
  5. Nasuha NA, Daud AH, Ghazali MM, Yusoff AA, Zainuddin N, Abdullah JM, et al.
    Asian J Surg, 2003 Apr;26(2):120-5.
    PMID: 12732498
    A case of pleomorphic xanthoastrocytoma in a 10-year-old Malay boy is reported. The patient presented with headache and epilepsy. On computed tomography, a ring-enhancing low-density lesion was observed in the left fronto-temporal area. During surgery, a cystic tumour containing serous fluid was found and almost totally removed. Histologically, the tumour exhibited marked pleomorphism of oval and spindle-shaped cells intermixed with uni- and multinucleated giant cells, and xanthomatous cells with foamy cytoplasm. The tumour displayed pericellular reticulin and periodic acid-Schiff positive granules. Focally, six mitotic characters per 10 high-power fields were seen, and necrosis was confined only to the inner lining of the cyst. Mutational analysis showed that a frameshift mutation (a 4-bp deletion) in the p53 gene had occurred in codons 273 and 274 of exon 8. No mutation was detected in the p16 gene. No allelic loss and/or loss of heterozygosity were observed on chromosome 10 using microsatellite marker D105532. The patient was treated with postoperative radiotherapy because of histological anaplasia and the presence of residual tumour. The patient showed marked neurological recovery after a follow-up period of 2 years.
    Matched MeSH terms: DNA Mutational Analysis
  6. Yusoff NM, Shirakawa T, Nishiyama K, Ghazali S, Ee CK, Orita A, et al.
    Int J Hematol, 2002 Aug;76(2):149-52.
    PMID: 12215013 DOI: 10.1007/BF02982577
    Multiplex polymerase chain reaction (PCR) using multiple tandem forward primers and a common reverse primer (MPTP) was recently established as a comprehensive screening method for mutations in X-linked recessive diseases. In the work reported here, MPTP was used to scan for mutations of the glucose-6-phosphate dehydrogenase (G6PD) gene. Mutations in exons 3,4,5,6,7,9, 11, and 12 of the G6PD gene were screened by MPTP in 93 unrelated Malaysian patients with G6PD deficiency. Of the 93 patients, 80 (86%) had identified mutations. Although all of these were missense mutations, identified nucleotide changes were heterogeneous, with 9 mutations involving various parts of the exons. These 9 mutations were G-to-A nucleotide changes at nucleotide 871 of the G6PD gene (G871A), corresponding to G6PD Viangchan, G6PD Mediterranean (C563T), G6PD Vanua Lava (T383C), G6PD Coimbra (C592T), G6PD Kaiping (G1388A), G6PD Orissa (C131G), G6PD Mahidol (G487A), G6PD Canton (G1376T), and G6PD Chatham (G1003A). Our results document heterogeneous mutations of the G6PD gene in the Malaysian population.
    Matched MeSH terms: DNA Mutational Analysis
  7. Looi ML, Sivalingam M, Husin ND, Radin FZ, Isa RM, Zakaria SZ, et al.
    Clin Chim Acta, 2011 May 12;412(11-12):999-1002.
    PMID: 21315703 DOI: 10.1016/j.cca.2011.02.006
    BACKGROUND: Beta thalassemia represents a great heterogeneity as over 300 mutations have been identified and each population at-risk has its own spectrum of mutations. Molecular characterization with high accuracy, sensitivity and economics is required for population screening and genetic counseling.
    METHODS: We used the MALDI-TOF mass spectrometry (MS) platform to develop novel multiplex assays for comprehensive detection of 27 mutations in beta-thalassemia patients. Six multiplex assays were designed to detect 13 common known ß-mutations, namely CD41/42, CD71/72, IVS1-5, IVS1-1, CD26, IVS2-654, CAP+1, CD19, -28, -29, IVS1-2, InCD (T-G) and CD17; and 14 rare ß-mutations, i.e. InCD (A-C), CD8/9, CD43, -86, CD15, Poly A, Poly T/C, IVS2-1, CD1, CD35/36, CD27/28, CD16, CD37, and 619bpDEL in 165 samples. We compared the efficiencies of genotyping by MS and Amplification Refractory Mutation System (ARMS). Discrepant results were confirmed by sequencing analysis.
    RESULTS: A total of 88.7% (260/293 allele) of MS and ARMS results was in agreement. More than fifty percent of the discrepant result was due to the false interpretation of ARMS results. Failed CD19 assay by MS method might be due to the assay design. The MS method detected 5 rare ß-mutations (CD15, CD35/36, CD8/9, Poly A and Poly T/C) presented in 13 alleles, which were not included in the ARMS screening panel.
    CONCLUSION: We revealed that the MS method is a sensitive, high-throughput, highly automated, flexible, and cost-effective alternative to conventional ß-thalassemia genotyping methods.
    Matched MeSH terms: DNA Mutational Analysis/methods*
  8. Tey S, Ahmad-Annuar A, Drew AP, Shahrizaila N, Nicholson GA, Kennerson ML
    Clin Genet, 2016 Aug;90(2):127-33.
    PMID: 26662454 DOI: 10.1111/cge.12712
    The cytoplasmic dynein-dynactin genes are attractive candidates for neurodegenerative disorders given their functional role in retrograde transport along neurons. The cytoplasmic dynein heavy chain (DYNC1H1) gene has been implicated in various neurodegenerative disorders, and dynactin 1 (DCTN1) genes have been implicated in a wide spectrum of disorders including motor neuron disease, Parkinson's disease, spinobulbar muscular atrophy and hereditary spastic paraplegia. However, the involvement of other dynactin genes with inherited peripheral neuropathies (IPN) namely, hereditary sensory neuropathy, hereditary motor neuropathy and Charcot-Marie-Tooth disease is under reported. We screened eight genes; DCTN1-6 and ACTR1A and ACTR1B in 136 IPN patients using whole-exome sequencing and high-resolution melt (HRM) analysis. Eight non-synonymous variants (including one novel variant) and three synonymous variants were identified. Four variants have been reported previously in other studies, however segregation analysis within family members excluded them from causing IPN in these families. No variants of disease significance were identified in this study suggesting the dynactin genes are unlikely to be a common cause of IPNs. However, with the ease of querying gene variants from exome data, these genes remain worthwhile candidates to assess unsolved IPN families for variants that may affect the function of the proteins.
    Matched MeSH terms: DNA Mutational Analysis
  9. Azize NA, Ngah WZ, Othman Z, Md Desa N, Chin CB, Md Yunus Z, et al.
    J Hum Genet, 2014 Nov;59(11):593-7.
    PMID: 25231368 DOI: 10.1038/jhg.2014.69
    Glycine encephalopathy (GCE) or nonketotic hyperglycinemia is an inborn error of glycine metabolism, inherited in an autosomal recessive manner due to a defect in any one of the four enzymes aminomethyltransferase (AMT), glycine decarboxylase (GLDC), glycine cleavage system protein-H (GCSH) and dehydrolipoamide dehydrogenase in the glycine cleavage system. This defect leads to glycine accumulation in body tissues, including the brain, and causes various neurological symptoms such as encephalopathy, hypotonia, apnea, intractable seizures and possible death. We screened 14 patients from 13 families with clinical and biochemical features suggestive of GCE for mutation in AMT, GLDC and GCSH genes by direct sequencing and genomic rearrangement of GLDC gene using a multiplex ligation-dependant probe amplification. We identified mutations in all 14 patients. Seven patients (50%) have biallelic mutations in GLDC gene, six patients (43%) have biallelic mutations in AMT gene and one patient (7%) has mutation identified in only one allele in GLDC gene. Majority of the mutations in GLDC and AMT were missense mutations and family specific. Interestingly, two mutations p.Arg265His in AMT gene and p.His651Arg in GLDC gene occurred in the Penan sub-population. No mutation was found in GCSH gene. We concluded that mutations in both GLDC and AMT genes are the main cause of GCE in Malaysian population.
    Matched MeSH terms: DNA Mutational Analysis/methods
  10. Zainal SA, Md Daud MK, Abd Rahman N, Zainuddin Z, Alwi Z
    Int J Pediatr Otorhinolaryngol, 2012 Aug;76(8):1175-9.
    PMID: 22613756 DOI: 10.1016/j.ijporl.2012.04.027
    To identify the mutations in the GJB2 gene and to determine its association with non-syndromic hearing loss in Malays.
    Matched MeSH terms: DNA Mutational Analysis
  11. Salahshourifar I, Wan Sulaiman WA, Halim AS, Zilfalil BA
    Eur J Med Genet, 2012 Jun;55(6-7):389-93.
    PMID: 22440537 DOI: 10.1016/j.ejmg.2012.02.006
    Non-syndromic oral clefts share the main clinical features of Van der Woude Syndrome (VWS), with the exception of the lower lip pit. Thus, about 15% of VWS cases are indistinguishable from cases with non-syndromic oral clefts. IRF6 mutations are the major cause of VWS; however, variants in this gene show strong association with non-syndromic oral clefts, with a higher increased risk among cases with cleft lip only (CLO). A total of 39 individuals, including 16 patients with CLO and 23 patients with a family history of cleft, were examined for IRF6 mutations in the present study. Seven variants, including five known (c.-75-4 A>; G, c.-73T>; C, c.459G>; T 5, c.820G>; A, and c.1060 + 37C>; T) and two novel (c.-75-23G>; C and c.1380G>; T), were found. Both novel variants were inherited from non-affected parents and we did not find also in the 120 control chromosomes. In silico analysis revealed that both c.1380G>; T and c.-75-23G>; C variants may disrupts a putative exonic splicing enhancer and intronic splicing binding site for SC35, respectively. Taken together, the presence of deleterious IRF6 variants in patients with non-syndromic oral clefts could be most likely an evidence for VWS. While, IRF6 variants could, at best, contribute to clefting as part of a complex inheritance pattern, with both additional genes and environmental factors having a role.
    Matched MeSH terms: DNA Mutational Analysis
  12. Chiu YH, Chang YC, Chang YH, Niu DM, Yang YL, Ye J, et al.
    J Hum Genet, 2012 Feb;57(2):145-52.
    PMID: 22237589 DOI: 10.1038/jhg.2011.146
    The enzyme 6-pyruvoyl-tetrahydropterin synthase (PTPS, gene symbol: PTS) is involved in the second step of the de novo biosynthesis of tetrahydrobiopterin (BH4), which is a vital cofactor of nitric oxide synthases and three types of aromatic amino acid hydroxylases; the latter are important enzymes in the production of neurotransmitters. We conducted a study of PTS mutations in East Asia, including Taiwan, Mainland China, Japan, South Korea, the Philippines, Thailand and Malaysia. A total of 43 mutations were identified, comprising 22 previously reported mutations and 21 new discovered mutations. Among these, the c.155A>G, c.259C>T, c. 272A>G, c.286G>A and c.84-291A>G mutations were the most common PTS mutations in East Asia, while the c.58T>C and c.243G>A mutations were, respectively, specific to Filipinos and Japanese originating from Okinawa. Further studies demonstrated that each of the mutations listed above was in linkage disequilibrium to a specific allele of polymorphic microsatellite marker, D11S1347. These results suggest the presence of founder effects that have affected these frequent mutations in East Asia populations. In this context, D11S1347 should become one of the most reliable polymorphic markers for use in prenatal diagnosis among PTPS deficient families, especially where mutations are yet to be identified.
    Matched MeSH terms: DNA Mutational Analysis*
  13. Rani AQ, Sasongko TH, Sulong S, Bunyan D, Salmi AR, Zilfalil BA, et al.
    J. Neurogenet., 2013 Jun;27(1-2):11-5.
    PMID: 23438214 DOI: 10.3109/01677063.2012.762580
    We undertook the clinical feature examination and dystrophin analysis using multiplex ligation-dependent probe amplification (MLPA) and direct DNA sequencing of selected exons in a cohort of 35 Malaysian Duchenne/Becker muscular dystrophy (DMD/BMD) patients. We found 27 patients with deletions of one or more exons, 2 patients with one exon duplication, 2 patients with nucleotide deletion, and 4 patients with nonsense mutations (including 1 patient with two nonsense mutations in the same exon). Although most cases showed compliance to the reading frame rule, we found two unrelated DMD patients with an in-frame deletion of the gene. Two novel mutations have been detected in the Dystrophin gene and our results were compatible with other studies where the majority of the mutations (62.8%) are located in the distal hotspot. However, the frequency of the mutations in our patient varied as compared with those found in other populations.
    Matched MeSH terms: DNA Mutational Analysis
  14. Numata S, Teye K, Krol RP, Karashima T, Fukuda S, Matsuda M, et al.
    J. Dermatol. Sci., 2015 Apr;78(1):82-5.
    PMID: 25766764 DOI: 10.1016/j.jdermsci.2015.02.006
    Matched MeSH terms: DNA Mutational Analysis
  15. Hung KL, Wang JS, Keng WT, Chen HJ, Liang JS, Ngu LH, et al.
    Pediatr Neurol, 2013 Sep;49(3):185-90.
    PMID: 23835273 DOI: 10.1016/j.pediatrneurol.2013.04.021
    X-linked adrenoleukodystrophy is caused by a defective peroxisomal membrane transporter, ABCD1, responsible for transporting very-long-chain fatty acid substrate into peroxisomes for degradation. The main biochemical defect, which is also one of the major diagnostic hallmarks, of X-linked adrenoleukodystrophy is the accumulation of saturated very-long-chain fatty acids in all tissues and body fluids.
    Matched MeSH terms: DNA Mutational Analysis
  16. Teh LK, Zahri MK, Zakaria ZA, Ismail R, Salleh MZ
    J Clin Pharm Ther, 2010 Dec;35(6):723-8.
    PMID: 21054465 DOI: 10.1111/j.1365-2710.2009.01146.x
    CYP2C8 is involved in the cytochrome P450 (CYP) epoxygenase pathway. Arachidonic acid metabolites such as epoxyeicosatrienenoic acids and hydroxyeicosatetrenoic acids, produced may have a role in hypertension. We aimed to develop a medium through-put method for screening samples of known and new mutations of CYP2C8 using denaturing high performance liquid chromatography (DHPLC).
    Matched MeSH terms: DNA Mutational Analysis
  17. Lau TY, Sylvi M, William T
    Malar J, 2013;12:445.
    PMID: 24321120 DOI: 10.1186/1475-2875-12-445
    The sulphadoxine/pyrimethamine (SDX/PYR) combination had been chosen to treat uncomplicated falciparum malaria in Malaysia for more than 30 years. Non-silent mutations in dihydrofolate reductase (dhfr) and dihydropteroate synthase (dhps) genes are responsible for the resistance to pyrimethamine and sulphadoxine, respectively. This study reports the mutational analysis of pfdhfr and pfdhps in single Plasmodium falciparum infection isolates from the interior division of Sabah, Malaysian Borneo.
    Matched MeSH terms: DNA Mutational Analysis
  18. Hoe SL, Sam CK
    Malays J Pathol, 2006 Jun;28(1):35-9.
    PMID: 17694957 MyJurnal
    This study reports the results of mutation detection of tumour suppressor genes, p53 and RB2/p130 genes in Malaysian nasopharyngeal carcinoma (NPC) studied by PCR-CSGE analysis and direct DNA sequencing method. Frequent sites of mutation in both genes (exons 5-8 of p53 and exons 19-21 of RB2/p130) were examined. Thirty-six NPC blood samples and three NPC cell lines were investigated for the presence of mutations. No mutation of p53 and RB2/p130 genes was identified in any of the blood samples. Nonetheless, there was an identical G-->4 C nucleotide change at codon 280 of p53 gene in all the cell lines. A larger study that includes biopsy tissues should be carried out to provide a more in-depth look into the pathogenesis of NPC in Malaysia.
    Matched MeSH terms: DNA Mutational Analysis
  19. Balraj P, Lim PG, Sidek H, Wu LL, Khoo AS
    J. Endocrinol. Invest., 2013 Jun;36(6):366-74.
    PMID: 23027774 DOI: 10.3275/8648
    Congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency (21-OHD) is a common autosomal recessive disorder. Our objective was to identify the 21-hydroxylase active gene, CYP21A2 mutations in Malaysian 21-OHD patients using different techniques.
    Matched MeSH terms: DNA Mutational Analysis
  20. Yusnita Y, Norsiah MD, Rahman AJ
    Malays J Pathol, 2010 Dec;32(2):103-10.
    PMID: 21329181 MyJurnal
    Mitochondrial Subunit ND1 (mtND1) gene is involved in the first step of the electron transport chain of oxidative phosphorylation (OXPHOS). Alteration of the electron transport components by mutations in mtDNA may compromise the normal electron flow. This could lead to an increase of bifurcation and generation of superoxidase radicals and increase oxidative stress in various types of cancer cells. Genomic DNA was extracted from thirty matched primary colorectal tumour tissues and matching non-tumour tissues. Blood samples were obtained from twenty-five normal people. The mtNDI coding region was amplified by step-down PCR. The purified products were then subjected to direct sequencing and subsequently, the DNA sequences obtained were compared with the revised Cambridge Reference Sequence (rCRS) and MITOMAP. From the analysis, the mtND1 gene showed 11 (45.8%) different mutations and also 13 (54.2%) polymorphisms. The heteroplasmic mutation A4123A/G (I273I/V) might have a pathogenic significance as it fulfills various pathogenic criteria. Three mutations, T3394C (Y30H), A3434G (Y43C) and C3497T (A64V) which occur in a highly conserved region were likely to alter the structure and function of the ND1 protein. We suggest that these mutations, and in combination with the polymorphic variance in mtDNA, may cause slight changes that generate subtly higher levels of toxic reactive oxygen species (ROS).
    Matched MeSH terms: DNA Mutational Analysis
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