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BamH1 polymorphism in the Chinese, Malays, and Indians in Singapore and its application in the prenatal diagnosis of beta-thalassemia

Tan JA, Tay SH, Kham KY, Wong HB

Jpn. J. Hum. Genet., 1993 Sep;38(3):315-8.
PMID: 7903173 DOI: 10.1007/BF01874141

The distribution of restriction fragment length polymorphism (RFLP) at the BamH1 site of the beta-globin gene was investigated in the Chinese, Indian, and Malay race in Singapore. The sample comprised of 183 normal individuals and 35 beta-thalassemia carriers in which 13 were couples with at least one beta-major child. The results from this study indicate that BamH1 polymorphism will be informative in 22% of pregnancies at risk for beta-thalassemia major in Chinese, 19% in Malays and 7% in Indians. In prenatal diagnosis using BamH1 polymorphism for one beta-major affected family, the fetus was diagnosed to be normal or beta-carrier. The validity of BamH1 polymorphism in the exclusion of beta-thalassemia major was subsequently confirmed at birth by globin chain biosynthesis.

Matched MeSH terms: Globins/genetics*; beta-Thalassemia/genetics
Oligonucleotide fingerprint analysis of strains of Getah virus isolated in Japan and Malaysia

Morita K, Igarashi A

J Gen Virol, 1984 Nov;65 ( Pt 11):1899-908.
PMID: 6094708

Eighteen strains of Getah virus isolated from mosquitoes, swine and horses in Japan (1956 to 1981), and one strain isolated in Malaysia (1955), were analysed by RNase T1-resistant oligonucleotide fingerprinting. All fingerprints showed a poly(A) tract. The fingerprint pattern of the Malaysian strain was quite different from those of the Japanese strains. Although most of the recent Japanese isolates shared many large oligonucleotide spots in common, the patterns were not identical even among the strains obtained in one locality in the same year. These results suggest that the Getah virus genome undergoes mutation rather frequently. However, there is a tendency for the isolates of the same year to show greater similarity. The fingerprint patterns of certain host-dependent temperature-sensitive (ts) mutants differed from that of the parental strain. Also, there were some differences in large oligonucleotide spots between strain JaNAr12380M isolated in suckling mouse brain (SMB) and strain JaNAr12380A isolated in C6/36 cells, despite the fact that both strains were derived from the same wild mosquito homogenate. In addition, many host-dependent ts mutants were present in strain JaNAr12380A, whereas no such mutants were observed in strain JaNAr12380M. It is concluded that there is considerable variation in the strains of Getah virus infecting mosquitoes in the wild, and also that the variants or mutants present in mosquitoes might be subject to selection during viral multiplication in the mammalian host.

Matched MeSH terms: Alphavirus/genetics*; RNA, Viral/genetics*
Nucleotide sequences of the nonstructural protein NS1 gene of three dengue-2 viruses, M1, M2 and M3, isolated in Malaysia from patients with dengue haemorrhagic fever, dengue shock syndrome and dengue fever, respectively

Fong MY, Koh CL, Samuel S, Pang T, Lam SK

Nucleic Acids Res, 1990 Mar 25;18(6):1642.
PMID: 2139210
Matched MeSH terms: Dengue Virus/genetics*; Viral Core Proteins/genetics*
Biochemical characteristics of glucose-6-phosphate dehydrogenase variants among the Malays of Singapore with report of a new non-deficient (GdSingapore) and three deficient variants

Saha N, Hong SH, Wong HA, Jeyaseelan K, Tay JS

Jinrui Idengaku Zasshi, 1991 Dec;36(4):307-12.
PMID: 1811096 DOI: 10.1007/BF01883603

Biochemical characteristics of one non-deficient fast G6PD variant (GdSingapore) and six different deficient variants (three new, two Mahidol, one each of Indonesian and Mediterranean) were studied among the Malays of Singapore. The GdSingapore variant had normal enzyme activity (82%) and fast electrophoretic mobilities (140% in TEB buffer, 160% in phosphate and 140% in Tris-HCl buffer systems respectively). This variant is further characterized by normal Km for G6P; utilization of analogues (Gal6P, 2dG6P; dAmNADP), heat stability and pH optimum. The other six deficient G6PD variants had normal electrophoretic mobility in TEB buffer with enzyme activities ranging from 1 to 12% of GdB+. The biochemical characteristics identity them to be 2 Mahidol, 1 Indonesian and 1 Mediterranean variants and three new deficient variants.

Matched MeSH terms: Glucosephosphate Dehydrogenase/genetics*; Glucosephosphate Dehydrogenase Deficiency/genetics*
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: Macaca fascicularis/genetics*; Vitamin D-Binding Protein/genetics*
Population genetic analysis of host seeking and resting behaviors in the malaria vector, Anopheles balabacensis (Diptera: Culicidae)

Hii JL, Chew M, Sang VY, Munstermann LE, Tan SG, Panyim S, et al.

J Med Entomol, 1991 Sep;28(5):675-84.
PMID: 1682492

During the intermonsoon period from mid-September to mid-October 1986, wild-caught Anopheles balabacensis Baisas females were marked and released in a host-choice experiment. Association between capture and recapture of marked mosquitoes from human and bovid hosts and blood meal host identification of recaptured females were determined on a daily basis. Although the mark-recapture and blood meal data indicated behavioral heterogeneity between buffalo and human biters, restriction endonuclease fragment length polymorphism analysis revealed no differences in repeat sequence profiles. Doubly-marked recaptures strongly indicated a "learning" component involved in a separate host preference experiment. In a "habitat loyalty" experiment conducted in January 1987, females of An. balabacensis preferentially returned to the resting sites (indoor surfaces and exit traps) where they were first caught. Of nine isozyme loci found to be polymorphic, the genotypic frequencies of Esterase-3 and Isocitrate dehydrogenase-3 were different in "faithfully" endophilic and exophilic subpopulations. Genetic heterozygosity, as determined by polyacrylamide gel electrophoresis, was greater in exophilic than endophilic population components. These results confirm that genetic and learning components can significantly influence house resting and host seeking behavior and may contribute to local epidemiological patterns of malaria transmission observed in Sabah, Malaysia.

Matched MeSH terms: Anopheles/genetics*; Insect Vectors/genetics*
Conjugal transfer of multiple antibiotic resistance from hospital isolates of Klebsiella to Escherichia coli

Koh CL, Lim ME, Wong YH

Southeast Asian J. Trop. Med. Public Health, 1983 Sep;14(3):336-40.
PMID: 6362015

Six independent isolates of Klebsiella from hospital environmental sources in Malaysia were found to be resistant to at least ampicillin, carbenicillin, cefoperazone, chloramphenicol, gentamicin and tetracycline. On the basis of their antibiograms, they were divided into four antibiogroups. They transferred all or part of their multiple antibiotic resistance traits to E. coli by conjugation. The results suggest that these Klebsiella strains harbour self-transmissible R plasmids. The significance of these findings are discussed.

Matched MeSH terms: Escherichia coli/genetics*; Klebsiella/genetics*
Genetic variation of Japanese encephalitis virus in nature

Chen WR, Tesh RB, Rico-Hesse R

J Gen Virol, 1990 Dec;71 ( Pt 12):2915-22.
PMID: 2273391

Forty-six strains of Japanese encephalitis (JE) virus from a variety of geographic areas in Asia were examined by primer-extension sequencing of the RNA template. A 240 nucleotide sequence from the pre-M gene region was selected for study because it provided sufficient information for determining genetic relationships among the virus isolates. Using 12% divergence as a cutoff point for virus relationships, the 46 isolates fell into three distinct genotypic groups. One genotypic group consisted of JE virus isolates from northern Thailand and Cambodia. A second group was composed of isolates from southern Thailand, Malaysia, Sarawak and Indonesia. The remainder of the isolates, from Japan, China, Taiwan, the Philippines, Sri Lanka, India and Nepal, made up a third group. The implications of these findings in relation to the epidemiology of JE are discussed. Results of this study demonstrate that the comparison of short nucleotide sequences can provide insight into JE virus evolution, transmission and, possibly, pathogenesis.

Matched MeSH terms: Encephalitis Virus, Japanese/genetics*; RNA, Viral/genetics*
Fulltext Nucleotide and encoded amino acid sequences of the capsid protein gene of three dengue-2 viruses isolated in Malaysia from patients with dengue haemorrhagic fever, dengue shock syndrome or dengue fever

Samuel S, Koh CL, Pang T, Lam SK

Nucleic Acids Res, 1990 Apr 11;18(7):1904.
PMID: 2336373
Matched MeSH terms: Dengue Virus/genetics*; Viral Structural Proteins/genetics*
Genetic variation in the malaria mosquito vector Anopheles maculatus from Peninsular Malaysia

Yong HS, Chiang GL, Loong KP, Ooi CS

Southeast Asian J. Trop. Med. Public Health, 1988 Dec;19(4):681-7.
PMID: 3238481

Starch-gel electrophoretic studies on nine gene-enzyme systems comprising 14 loci revealed a fair level of genetic variation in two population samples of Anopheles maculatus from Peninsular Malaysia. The proportion of polymorphic loci was 0.36 for the Fort Bertau sample and 0.29 for the Gua Musang sample, while the mean heterozygosity value was 0.09 for Fort Bertau and 0.07 for Gua Musang. The values of genetic similarity (I = 0.98) and genetic distance (D = 0.02) were of the rank of geographical populations.

Matched MeSH terms: Anopheles/genetics*; Insect Vectors/genetics*
Kin-structured migration: causes and consequences

Fix AG

Am J Hum Biol, 2004 Jul-Aug;16(4):387-94.
PMID: 15214057

Migration among local populations classically has been seen as the principal process retarding genetic microdifferentiation. However, as Sewall Wright pointed out long ago, migration may also act as a random differentiating force. In fact, when migrants comprise a biological kin group, migration may be considered a component of genetic drift. The causes of kin-structured migration (KSM) lie in the common, if not universal, tendency for kin to associate and cooperate. However, similar to genetic drift, KSM has its greatest effect in smaller populations and is most apparent in low-density fission-fusion societies such as the Yanomamo of South America and the Semai of Malaysia, and less salient in higher density, low-mobility populations such as those of the New Guinea Highlands. The evolutionary consequences of KSM begin with increased genetic variation among populations. Such intergroup variation provides a basis for group selection. The origin of larger-scale geographic differentiation can arise from kin-structured migrant groups colonizing new regions. Waves of colonizing kin-structured founder groups may produce gene frequency clines, mimicking demic diffusion and natural selection. Finally, because kin structuring reduces the effective size of a population, it may be speculated that the extremely small effective size inferred for ancestral populations of Homo sapiens may be an artifact of kin-structured demographically larger populations.

Matched MeSH terms: Hemoglobin E/genetics; Genetic Variation/genetics*
BRCA1 c.2845insA is a founder mutation in Singaporean Malay women with early onset breast/ovarian cancer

Sng JH, Ali AB, Lee SC, Zahar D, Wong JE, Cross G, et al.

Ann Acad Med Singap, 2003 Sep;32(5 Suppl):S53-5.
PMID: 14968737
Matched MeSH terms: Breast Neoplasms/genetics*; Ovarian Neoplasms/genetics*
Fulltext Immunohistochemical localization of RET rearrangements in a Malaysian papillary thyroid carcinoma population

Omar E, Othman NH

Med J Malaysia, 2003 Aug;58(3):461-2.
PMID: 14750392
Matched MeSH terms: Oncogene Proteins/genetics*; Receptor Protein-Tyrosine Kinases/genetics*
Quantitative trait loci in Anopheles gambiae controlling the encapsulation response against Plasmodium cynomolgi Ceylon

Zheng L, Wang S, Romans P, Zhao H, Luna C, Benedict MQ

BMC Genet, 2003 Oct 24;4:16.
PMID: 14577840

Anopheles gambiae females are the world's most successful vectors of human malaria. However, a fraction of these mosquitoes is refractory to Plasmodium development. L3-5, a laboratory selected refractory strain, encapsulates transforming ookinetes/early oocysts of a wide variety of Plasmodium species. Previous studies on these mosquitoes showed that one major (Pen1) and two minor (Pen2, Pen3) autosomal dominant quantitative trait loci (QTLs) control the melanotic encapsulation response against P. cynomolgi B, a simian malaria originating in Malaysia.

Matched MeSH terms: Anopheles/genetics*; Insect Vectors/genetics*
Haemoglobin S in Malays and Indians: association of Hb CoSp and Hb S in a Malay family

Saidi HT, Duraisamy G

Trop Geogr Med, 1978 Mar;30(1):103-8.
PMID: 675819

Four cases of Hb S were seen between Jan. 1976 and June 1976; three of them were newly discovered while the fourth was previously diagnosed. Out of the four cases, two were Malays and the other Indians. The family members of one Malay case were investigated. Six members had Hb S and three had Hb CoSp. Association of Hb CoSp and Hb S was seen in two of the members. Clinically they were healthy.

Matched MeSH terms: Anemia, Sickle Cell/genetics*; Sickle Cell Trait/genetics*
Immunogenetic aspects of nasopharyngeal carcinoma: I. Differences in HL-A antigen profiles between patients and control groups

Simons MJ, Wee GB, Day NE, Morris PJ, Shanmugaratnam K, De-Thé GB

Int J Cancer, 1974 Jan 15;13(1):122-34.
PMID: 4131857
Matched MeSH terms: Carcinoma/genetics; Immunogenetics; Nasopharyngeal Neoplasms/genetics
Fulltext Association of MMP-9 gene polymorphisms with nephrolithiasis patients

Mehde AA, Mehdi WA, Yusof F, Raus RA, Zainal Abidin ZA, Ghazali H, et al.

J Clin Lab Anal, 2018 Jan;32(1).
PMID: 28205286 DOI: 10.1002/jcla.22173

BACKGROUND: Nephrolithiasis is one of the causes which lead to chronic kidney disease (CKD). Matrix metalloproteinases (MMPs) are endopeptidases degrading extracellular matrix which correlate with the pathogenesis of atherosclerosis. The current study was designed to analyze the association of (R279Q, C1562T) polymorphism of MMP-9 with nephrolithiasis patients.
METHODS: Genotyping of MMP-9/R279Q and of MMP-9/C1562T polymorphism were carried out by PCR-based restriction digestion method. Serum level of MMP-9, oxidative stress marker, MDA, and uric acid were measured in patients and control.
RESULTS: Allele frequencies of the MMP-9/C1562T polymorphism for C and T allele were 71.25% and 28.75% in patients, 87.08% and 12.92% in control respectively. The homozygote TT was more frequent in the nephrolithiasis patients group, while T allele frequency was significantly higher in the nephrolithiasis patients group than in the control group. The patients with CT and TT genotype showed a significant increase in serum MMP-9, Total Oxidant Status (TOS), Oxidative Stress Index (OSI), Malondialdehyde (MDA), and uric acid when compared to CC genotype in patients with nephrolithiasis. The R279Q polymorphism site with regard to the relationship with nephrolithiasis was not significant.
CONCLUSION: The result indicates that patients with TT genotype had an increased risk of stones. Also, the results demonstrate that TT allele of the C1562T polymorphism in the MMP-9gene is related with an increase of oxidative stress in nephrolithiasis patients and may possibly impose a risk for cardiovascular diseases in patients with TT genotype of MMP-9.

Matched MeSH terms: Matrix Metalloproteinase 9/genetics*; Nephrolithiasis/genetics*
Fulltext Issues in identifying germ tube positive yeasts by conventional methods

Yazdanpanah A, Khaithir TM

J Clin Lab Anal, 2014 Jan;28(1):1-9.
PMID: 24375729 DOI: 10.1002/jcla.21635

Candida speciation is vital for epidemiology and management of candidiasis. Nonmolecular conventional methods often fail to identify closely related germ tube positive yeasts from clinical specimens. The present study was conducted to identify these yeasts and to highlight issues in conventional versus molecular methods of identification. A total of 98 germ tube positive yeasts from high vaginal swabs were studied over a 12-month period. Isolates were examined with various methods including growth at 42 °C and 45 °C on Sabouraud dextrose agar (SDA), color development on CHROMagar Candida medium, chlamydospore production on corn meal agar at 25 °C, carbohydrate assimilation using ID 32C system, and polymerase chain reaction using a single pair of primers targeting the hyphal wall protein 1 (Hwp1) gene. Of all the isolates studied, 97 were molecularly confirmed as C. albicans and one isolate was identified as C. dubliniensis. No C. africana was detected in this study. The molecular method used in our study was an accurate and useful tool for discriminating C. albicans, C. dubliniensis, and C. africana. The conventional methods, however, were less accurate and riddled with many issues that will be discussed in further details.

Matched MeSH terms: Candida/genetics; DNA, Fungal/genetics
FOXRED1 silencing in mice: a possible animal model for Leigh syndrome

Salama M, El-Desouky S, Alsayed A, El-Hussiny M, Moustafa A, Taalab Y, et al.

Metab Brain Dis, 2019 02;34(1):367-372.
PMID: 30392038 DOI: 10.1007/s11011-018-0334-z

Leigh syndrome (LS) is one of the most puzzling mitochondrial disorders, which is also known as subacute necrotizing encephalopathy. It has an incidence of 1 in 77,000 live births worldwide with poor prognosis. Currently, there is a poor understanding of the underlying pathophysiological mechanisms of the disease without any available effective treatment. Hence, the inevitability for developing suitable animal and cellular models needed for the development of successful new therapeutic modalities. In this short report, we blocked FOXRED1 gene with small interfering RNA (siRNA) using C57bl/6 mice. Results showed neurobehavioral changes in the injected mice along with parallel degeneration in corpus striatum and sparing of the substantia nigra similar to what happen in Leigh syndrome cases. FOXRED1 blockage could serve as a new animal model for Leigh syndrome due to defective CI, which echoes damage to corpus striatum and affection of the central dopaminergic system in this disease. Further preclinical studies are required to validate this model.

Matched MeSH terms: Leigh Disease/genetics*; Molecular Chaperones/genetics*
Prevalence and ethnic differences of autosomal-dominant cerebellar ataxia in Singapore

Zhao Y, Tan EK, Law HY, Yoon CS, Wong MC, Ng I

Clin Genet, 2002 Dec;62(6):478-81.
PMID: 12485197

We report the prevalence and ethnic differences of autosomal-dominant cerebellar ataxia (ADCA) in Singapore. Amongst 204 patients with ataxia who underwent genetic testing for dentatorubral-pallidoluysian atrophy (DRPLA) and for spinocerebellar ataxias (SCA) 1, 2, 3, 6, 7, 8, 10 and 12, 58 (28.4%) patients from 36 families tested positive. SCA 3 was identified in 31 (53.4%) patients from 15 families, SCA 2 in 17 (29.3%) patients from 12 families and SCA 1 in four (6.9%) patients from four families. Other SCA subtypes were rare. SCA 2 was the only subtype identified amongst ethnic Malay and ethnic Indian families. The estimated prevalence of ADCA in Singaporean families was at least 1 : 27,000. Based on the history and ancestry of Singaporeans, our study supported a founder effect for specific SCA subtypes and the association of ethnicity-specific SCA subtypes. Our findings suggest that SCA 2 is relatively common amongst the Malay race and that priority testing for SCA 3 and SCA 2 for ethnic Chinese, and SCA 2 for ethnic Malay, may be cost effective and relevant for the region.

Matched MeSH terms: Cerebellar Ataxia/genetics*; Ethnic Groups/genetics*

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