Displaying publications 1 - 20 of 144 in total

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  1. Fulltext Zinc transporter-3 [SLC30A3(rs11126936)]polymorphismis associated with major depressive disorderin Asian subjects
    Lye, Munn-Sann, Aishah-Farhana Shahbudin, Tey, Yin-Yee, Tor, Yin-Sim, Ling, King-Hwa, Normala Ibrahim, et al.
    Neuroscience Research Notes, 2019;2(3):20-28.
    MyJurnal
    Major depressive disorder (MDD) compromises the individual’s capacity for self-care and productivity. Single nucleotide polymorphisms (SNP) of a number of genes have been associated with MDD. The zinc transporter-3 protein, encoded by the ZnT3 (SLC30A3) gene, maintains zinc-glutamate homeostasis at the glutamatergic synapse, a disruption of which increases risk of MDD. We hypothesise that variation in SLC30A3 (rs11126936)SNP increases risk of MDD. We recruited 300 MDD cases and 300 controls, matched in theratio of 1:1 by age, gender and ethnicity. PCR-restriction fragment length polymorphism analysis was used in DNA genotyping, validated by sequencing 10%of samples. Deviation from the Hardy-Weinberg equilibrium was tested using the chi-square test. Conditional logistic regression was used to estimate adjusted odds ratios, controlling for age, gender, ethnicity, occupation and family monthly income.Genotypes G/G and G/T showed two times greater odds of developing MDD compared to variant genotype T/T (OR=1.983, 95% CI=1.031-3.815; p=0.040 and OR=2.232, 95% CI=1.100-4.533; p=0.026 respectively). Carriers of genotypes G/G and G/T of the SNP rs11126936 in SLC30A3are associated with increased risk of MDD.
    Matched MeSH terms: Heterozygote
  2. Fulltext XPC Lys939Gln polymorphism, smoking and risk of sporadic colorectal cancer among Malaysians
    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: Heterozygote
  3. Fulltext Wilson's disease--a review of cases at University Hospital, Kuala Lumpur
    Mohamed R, Tan CT, Wong NW
    Med J Malaysia, 1994 Mar;49(1):49-52.
    PMID: 8057991
    The clinical course of 18 patients with Wilson's disease is reported. There were 13 males and five females of whom one is Malay. The prevalence of Wilson's disease in Malaysia is probably the same as elsewhere. Being a genetic syndrome, the genetic carrier rate for Wilson's disease is probably lower amongst the Malays. At diagnosis, the clinical signs were predominantly hepatic in 10 patients, neurological in five patients with three asymptomatic cases. All patients were commenced on penicillamine but poor compliance was observed in many patients. Two patients defaulted follow-up and seven patients died. Out of the nine surviving patients, only four are well with no clinical symptoms.
    Matched MeSH terms: Heterozygote
  4. Fulltext Whole-genome sequencing analysis of phenotypic heterogeneity and anticipation in Li-Fraumeni cancer predisposition syndrome
    Ariffin H, Hainaut P, Puzio-Kuter A, Choong SS, Chan AS, Tolkunov D, et al.
    Proc Natl Acad Sci U S A, 2014 Oct 28;111(43):15497-501.
    PMID: 25313051 DOI: 10.1073/pnas.1417322111
    The Li-Fraumeni syndrome (LFS) and its variant form (LFL) is a familial predisposition to multiple forms of childhood, adolescent, and adult cancers associated with germ-line mutation in the TP53 tumor suppressor gene. Individual disparities in tumor patterns are compounded by acceleration of cancer onset with successive generations. It has been suggested that this apparent anticipation pattern may result from germ-line genomic instability in TP53 mutation carriers, causing increased DNA copy-number variations (CNVs) with successive generations. To address the genetic basis of phenotypic disparities of LFS/LFL, we performed whole-genome sequencing (WGS) of 13 subjects from two generations of an LFS kindred. Neither de novo CNV nor significant difference in total CNV was detected in relation with successive generations or with age at cancer onset. These observations were consistent with an experimental mouse model system showing that trp53 deficiency in the germ line of father or mother did not increase CNV occurrence in the offspring. On the other hand, individual records on 1,771 TP53 mutation carriers from 294 pedigrees were compiled to assess genetic anticipation patterns (International Agency for Research on Cancer TP53 database). No strictly defined anticipation pattern was observed. Rather, in multigeneration families, cancer onset was delayed in older compared with recent generations. These observations support an alternative model for apparent anticipation in which rare variants from noncarrier parents may attenuate constitutive resistance to tumorigenesis in the offspring of TP53 mutation carriers with late cancer onset.
    Matched MeSH terms: Heterozygote
  5. Fulltext Two cases of deletion 5p syndrome: one with paternal involvement and another with atypical presentation
    Azman BZ, Akhir SM, Zilfalil BA, Ankathil R
    Singapore Med J, 2008 Apr;49(4):e98-e100.
    PMID: 18418516
    We report two cases of deletion 5p or cri du chat syndrome (CdCS) with different presentations and risks of transmission: one case with paternal chromosome 5 involvement and another, a de novo case with atypical clinical presentation. Cytogenetic analysis was performed on the two cases and their parents. GTG-banded karyotype analysis of Cases 1 and 2 revealed abnormal 46,XY,del(5)(p13-15) male karyotypes. For Case 1, the mother showed normal female karyotype while the father showed an abnormal karyotype involving a balanced translocation 46,XY,t(5;10)(p13;p15). For Case 2, however, both parents showed a normal karyotype pattern. In Case 1, the clinical features, particularly the distinct facial phenotype in combination with a characteristic cat-like cry and hypotonia, aided in the diagnosis at birth and the karyotype analysis was resolutive. The boy in Case 2 presented with atypical clinical features. Even though this patient had multiple syndromic features, the typical high pitched cat-like cry was not prominent. Instead, the patient manifested persistent stridor (from day three of life), which might have prevented the clinician from suspecting CdCS at birth. However, when this patient was presented at seven months of age for cytogenetic analysis, a confirmatory diagnosis of CdCS was established. For children with congenital abnormalities, an early clinical diagnosis confirmed through cytogenetic and molecular investigations, is important for providing personalised diagnostic and prognostic evaluation, and also for genetic counselling on the reproductive risk, particularly for patients with parental chromosome translocation involvement.
    Matched MeSH terms: Heterozygote Detection*
  6. Fulltext Tropical distal renal tubular acidosis: clinical and epidemiological studies in 78 patients
    Khositseth S, Bruce LJ, Walsh SB, Bawazir WM, Ogle GD, Unwin RJ, et al.
    QJM, 2012 Sep;105(9):861-77.
    PMID: 22919024 DOI: 10.1093/qjmed/hcs139
    Distal renal tubular acidosis (dRTA) caused by mutations of the SLC4A1 gene encoding the erythroid and kidney isoforms of anion exchanger 1 (AE1 or band 3) has a high prevalence in some tropical countries, particularly Thailand, Malaysia, the Philippines and Papua New Guinea (PNG). Here the disease is almost invariably recessive and can result from either homozygous or compound heterozygous SLC4A1 mutations.
    Matched MeSH terms: Heterozygote
  7. Fulltext Thrombocytopenia and CD34 expression is decoupled from α-granule deficiency with mutation of the first growth factor-independent 1B zinc finger
    Rabbolini DJ, Morel-Kopp MC, Chen Q, Gabrielli S, Dunlop LC, Chew LP, et al.
    J Thromb Haemost, 2017 Nov;15(11):2245-2258.
    PMID: 28880435 DOI: 10.1111/jth.13843
    Essentials The phenotypes of different growth factor-independent 1B (GFI1B) variants are not established. GFI1B variants produce heterogeneous clinical phenotypes dependent on the site of mutation. Mutation of the first non-DNA-binding zinc-finger causes a mild platelet and clinical phenotype. GFI1B regulates the CD34 promoter; platelet CD34 expression is an indicator of GFI1B mutation.

    SUMMARY: Background Mutation of the growth factor-independent 1B (GFI1B) fifth DNA-binding zinc-finger domain causes macrothrombocytopenia and α-granule deficiency leading to clinical bleeding. The phenotypes associated with GFI1B variants disrupting non-DNA-binding zinc-fingers remain uncharacterized. Objectives To determine the functional and phenotypic consequences of GFI1B variants disrupting non-DNA-binding zinc-finger domains. Methods The GFI1B C168F variant and a novel GFI1B c.2520 + 1_2520 + 8delGTGGGCAC splice variant were identified in four unrelated families. Phenotypic features, DNA-binding properties and transcriptional effects were determined and compared with those in individuals with a GFI1B H294 fs mutation of the fifth DNA-binding zinc-finger. Patient-specific induced pluripotent stem cell (iPSC)-derived megakaryocytes were generated to facilitate disease modeling. Results The DNA-binding GFI1B variant C168F, which is predicted to disrupt the first non-DNA-binding zinc-finger domain, is associated with macrothrombocytopenia without α-granule deficiency or bleeding symptoms. A GFI1B splice variant, c.2520 + 1_2520 + 8delGTGGGCAC, which generates a short GFI1B isoform that lacks non-DNA-binding zinc-fingers 1 and 2, is associated with increased platelet CD34 expression only, without quantitative or morphologic platelet abnormalities. GFI1B represses the CD34 promoter, and this repression is attenuated by different GFI1B zinc-finger mutations, suggesting that deregulation of CD34 expression occurs at a direct transcriptional level. Patient-specific iPSC-derived megakaryocytes phenocopy these observations. Conclusions Disruption of GFI1B non-DNA-binding zinc-finger 1 is associated with mild to moderate thrombocytopenia without α-granule deficiency or bleeding symptomatology, indicating that the site of GFI1B mutation has important phenotypic implications. Platelet CD34 expression appears to be a common feature of perturbed GFI1B function, and may have diagnostic utility.

    Matched MeSH terms: Heterozygote
  8. Fulltext Three cases of permanent neonatal diabetes mellitus: genotypes and management outcome
    Ooi HL, Wu LL
    Singapore Med J, 2012 Jul;53(7):e142-4.
    PMID: 22815030
    Neonatal diabetes mellitus (DM) is defined as insulin-requiring DM in the first six months of life. Unlike type 1 DM, it is a monogenic disorder resulting from a de novo mutation in the genes involved in the development of the pancreas, β-cell mass or secretory function. The majority of neonatal DM cases are caused by a heterozygous activating mutation in the KCNJ11 or ABCC8 genes that encode the Kir6.2 and SUR1 protein subunits, respectively, in the KATP channel. Sulphonylurea, a KATP channel inhibitor, can restore insulin secretion, hence offering an attractive alternative to insulin therapy. We report three cases of neonatal DM and their genetic mutations. Two patients were successfully switched over to sulphonylurea monotherapy with resultant improvement in the quality of life and a more stable blood glucose profile. Patients with neonatal DM should undergo genetic evaluation. For patients with KCNJ11 and ABCC8 gene mutation, oral sulphonylurea should be considered.
    Matched MeSH terms: Heterozygote
  9. Fulltext The suitability of P. falciparum merozoite surface proteins 1 and 2 as genetic markers for in vivo drug trials in Yemen
    Al-abd NM, Mahdy MA, Al-Mekhlafi AM, Snounou G, Abdul-Majid NB, Al-Mekhlafi HM, et al.
    PLoS One, 2013;8(7):e67853.
    PMID: 23861823 DOI: 10.1371/journal.pone.0067853
    The accuracy of the conclusions from in vivo efficacy anti-malarial drug trials depends on distinguishing between recrudescences and re-infections which is accomplished by genotyping genes coding P. falciparum merozoite surface 1 (MSP1) and MSP2. However, the reliability of the PCR analysis depends on the genetic markers' allelic diversity and variant frequency. In this study the genetic diversity of the genes coding for MSP1 and MSP2 was obtained for P. falciparum parasites circulating in Yemen.
    Matched MeSH terms: Heterozygote
  10. Fulltext The spectrum of beta-thalassemia mutations in Malays in Singapore and Kelantan
    Abdullah WA, Jamaluddin NB, Kham SK, Tan JA
    Southeast Asian J. Trop. Med. Public Health, 1996 Mar;27(1):164-8.
    PMID: 9031421
    The spectrum of beta-thalassemia mutations in Malays in Singapore and Kelantan (Northeast Malaysia) was studied. Allele specific priming was used to determine the mutations in beta-carriers at -28, Codon 17, IVSI #1, IVSI #5, Codon 41-42 and IVSII #654 along the beta-globin gene. The most common structural hemoglobin variant in Southeast Asia, Hb E, was detected by DNA amplification with restriction enzyme (Mnl1) analysis. Direct genomic sequencing was carried out to detect the beta-mutations uncharacterized by allele-specific priming. The most prevalent beta-mutations in Singaporean Malays were IVSI #5 (45.83%) followed by Hb E (20.83%), codon 15 (12.5%) and IVSI #1 and IVSII #654 at 4.17% each. In contrast, the distribution of the beta-mutations in Kelantan Malays differed, with Hb E as the most common mutation (39.29%) followed by IVSI #5 (17.86%), codon 41-42 (14.29%), codon 19 (10.71%) and codon 17 (3.57%). The beta-mutations in Kelantan Malays follow closely the distribution of beta-mutations in Thais and Malays of Southern Thailand and Malays of West Malaysia. The AAC-->AGC base substitution in codon 19 has been detected only in these populations. The spectrum of beta-mutations in the Singaporean Malays is more similar to those reported in Indonesia with the beta-mutation at codon 15 (TGG-->TAG) present in both populations. The characterization of beta-mutations in Singaporean and Kelantan Malays will facilitate the establishment of effective prenatal diagnosis programs for beta-thalassemia major in this ethnic group.
    Matched MeSH terms: Heterozygote Detection
  11. Fulltext The predictive ability of the 313 variant-based polygenic risk score for contralateral breast cancer risk prediction in women of European ancestry with a heterozygous BRCA1 or BRCA2 pathogenic variant
    Lakeman IMM, van den Broek AJ, Vos JAM, Barnes DR, Adlard J, Andrulis IL, et al.
    Genet Med, 2021 Sep;23(9):1726-1737.
    PMID: 34113011 DOI: 10.1038/s41436-021-01198-7
    PURPOSE: To evaluate the association between a previously published 313 variant-based breast cancer (BC) polygenic risk score (PRS313) and contralateral breast cancer (CBC) risk, in BRCA1 and BRCA2 pathogenic variant heterozygotes.

    METHODS: We included women of European ancestry with a prevalent first primary invasive BC (BRCA1 = 6,591 with 1,402 prevalent CBC cases; BRCA2 = 4,208 with 647 prevalent CBC cases) from the Consortium of Investigators of Modifiers of BRCA1/2 (CIMBA), a large international retrospective series. Cox regression analysis was performed to assess the association between overall and ER-specific PRS313 and CBC risk.

    RESULTS: For BRCA1 heterozygotes the estrogen receptor (ER)-negative PRS313 showed the largest association with CBC risk, hazard ratio (HR) per SD = 1.12, 95% confidence interval (CI) (1.06-1.18), C-index = 0.53; for BRCA2 heterozygotes, this was the ER-positive PRS313, HR = 1.15, 95% CI (1.07-1.25), C-index = 0.57. Adjusting for family history, age at diagnosis, treatment, or pathological characteristics for the first BC did not change association effect sizes. For women developing first BC 

    Matched MeSH terms: Heterozygote
  12. The population genomic landscape of human genetic structure, admixture history and local adaptation in Peninsular Malaysia
    Deng L, Hoh BP, Lu D, Fu R, Phipps ME, Li S, et al.
    Hum Genet, 2014 Sep;133(9):1169-85.
    PMID: 24916469 DOI: 10.1007/s00439-014-1459-8
    Peninsular Malaysia is a strategic region which might have played an important role in the initial peopling and subsequent human migrations in Asia. However, the genetic diversity and history of human populations--especially indigenous populations--inhabiting this area remain poorly understood. Here, we conducted a genome-wide study using over 900,000 single nucleotide polymorphisms (SNPs) in four major Malaysian ethnic groups (MEGs; Malay, Proto-Malay, Senoi and Negrito), and made comparisons of 17 world-wide populations. Our data revealed that Peninsular Malaysia has greater genetic diversity corresponding to its role as a contact zone of both early and recent human migrations in Asia. However, each single Orang Asli (indigenous) group was less diverse with a smaller effective population size (N(e)) than a European or an East Asian population, indicating a substantial isolation of some duration for these groups. All four MEGs were genetically more similar to Asian populations than to other continental groups, and the divergence time between MEGs and East Asian populations (12,000--6,000 years ago) was also much shorter than that between East Asians and Europeans. Thus, Malaysian Orang Asli groups, despite their significantly different features, may share a common origin with the other Asian groups. Nevertheless, we identified traces of recent gene flow from non-Asians to MEGs. Finally, natural selection signatures were detected in a batch of genes associated with immune response, human height, skin pigmentation, hair and facial morphology and blood pressure in MEGs. Notable examples include SYN3 which is associated with human height in all Orang Asli groups, a height-related gene (PNPT1) and two blood pressure-related genes (CDH13 and PAX5) in Negritos. We conclude that a long isolation period, subsequent gene flow and local adaptations have jointly shaped the genetic architectures of MEGs, and this study provides insight into the peopling and human migration history in Southeast Asia.
    Matched MeSH terms: Heterozygote
  13. The isolation and characterization of microsatellites from Anopheles dirus mosquitoes
    Walton C, Chang MS, Handley JM, Harbach RE, Collins FH, Baimai V, et al.
    Mol Ecol, 2000 Oct;9(10):1665-7.
    PMID: 11050564
    Matched MeSH terms: Heterozygote
  14. The genetic structure of Oreochromis spp. (Tilapia) populations in Malaysia as revealed by microsatellite DNA analysis
    Bhassu S, Yusoff K, Panandam JM, Embong WK, Oyyan S, Tan SG
    Biochem Genet, 2004 Aug;42(7-8):217-29.
    PMID: 15487586
    The genetic make-up of five populations of Oreochromis spp. was examined by microsatellite analysis. Eleven polymorphic microsatellite loci showed significant departures from the Hardy-Weinberg equilibrium. The mean heterozygosity ranged from 0.6280 to 0.7040 for each population. The genetic distance values showed a clear separation between O. niloticus and O. mossambicus. The differentiation of the O. niloticus populations was then tested with various genetic measures, which are based on both the Infinite Allele and the Stepwise Mutation models. All these measures grouped the populations similarly.
    Matched MeSH terms: Heterozygote
  15. Fulltext Thalassaemia screening among healthy blood donors in Hospital Tengku Ampuan Rahimah, Klang
    Irmi Elfina, R., Ezalia, E., Elizabeth, G., Wan Hayati, M.Y, Norhanim, A., Wahidah, A., et al.
    Medicine & Health, 2014;9(1):44-52.
    MyJurnal
    Thalassaemia screening programme has been conducted in Malaysia since 2004. The aim of the programme was to reduce the burden of the disease by identifying thalassaemia carriers. However, the response towards the screening activities was unsatisfactory as there was lack of public awareness against the importance of thalassaemia screening. An alternative approach is to screen blood donors. The purpose of this study was to observe the prevalence of thalassaemia carriers among healthy blood donors. Seven hundred and thirty eight healthy blood donors were screened in Hospital Tengku Ampuan Rahimah, Klang from July to September 2010 using cation-exchange high performance liquid chromatography (HPLC). Cases with haemoglobin variants were further analyzed by gel electrophoresis at alkaline pH. Result shows that the blood donors consisted of 413 Malays (56%), 162 Indians (22%), 148 Chinese (20%) and 15 others (2%). There were 19 (2.6%) individuals with haemoglobin E trait, six (0.8%) with co-inheritance of haemoglobin E and αα- thalassaemia and five (0.7%) with β-thalassaemia trait. Haemoglobin Constant Spring and haemoglobin A2 prime were observed in two (0.3%); and Haemoglobin Lepore and alpha chain variant in one (0.2%). αα-thalassaemia and normal haemoglobin A2 β-thalassaemia could not be excluded in 190 cases (26%), as they required deoxyribonucleic acid (DNA) studies for identification. Thalassaemia screening in blood donors is more feasible and effective. Therefore, a wider scale population screening including blood donors could benefit the existing thalassaemia screening programme in Malaysia.
    Matched MeSH terms: Heterozygote
  16. Study of the D-- phenotype reveals erythrocyte membrane alterations in the absence of RHCE
    Flatt JF, Musa RH, Ayob Y, Hassan A, Asidin N, Yahya NM, et al.
    Br J Haematol, 2012 Jul;158(2):262-273.
    PMID: 22571328 DOI: 10.1111/j.1365-2141.2012.09149.x
    Red cells with the D-- phenotype do not express the RHCE protein because of mutations in both alleles of the RHCE gene. At present, little is known of the effect this has on the normal function of erythrocytes. In this study a group of five families belonging to a nomadic tribe in Malaysia were identified as carriers of the D-- haplotype. Analysis of homozygous individuals' genomic DNA showed two separate novel mutations. In four of the families, RHCE exons 1, 9 and 10 were present, while the 5th family possessed RHCE exons 1-3 and 10. Analysis of cDNA revealed hybrid transcripts, suggesting a gene conversion event with RHD, consistent with previously reported D-- mutations. Immunoblotting analysis of D-- erythrocyte membrane proteins found that Rh-associated glycoprotein (RHAG) migrates with altered electrophoretic mobility on sodium dodecyl sulphate polyacrylamide gel electrophoresis, consistent with increased glycosylation. Total amounts of Rh polypeptide in D-- membranes were comparable with controls, indicating that the exalted D antigen displayed by D-- red cells may be associated with altered surface epitope presentation. The adhesion molecules CD44 and CD47 are significantly reduced in D--. Together these results suggest that absence of RHCE polypeptide alters the structure and packing of the band 3/Rh macrocomplex.
    Matched MeSH terms: Heterozygote
  17. Siriraj I Gγ(Aγδβ)0-thalassaemia causing severe thalassaemia intermedia in compound heterozygous state with IVS1-1(G→T) mutation
    Wong YY, Alauddin H, Raja Sabudin RZA, Ithnin A, Jalil N, Abdul Latiff Z, et al.
    Malays J Pathol, 2021 Apr;43(1):95-100.
    PMID: 33903312
    The Siriraj I Gγ(Aγδβ)0-thalassaemia is a novel mutation involving a 118kb deletion of the β-globin gene cluster. It was first reported in 2012 in two unrelated families from the southern part of Thailand. The carriers in the heterozygous state are clinically asymptomatic. Nonetheless, its complex interaction with other β-thalassaemia could give rise to different clinical phenotypes, ranging from mild thalassaemia intermedia to thalassaemia major. We report here a case of a six-year-old Malay boy, presented with pallor, growth failure and hepatosplenomegaly. His haemoglobin at presentation was 9.2g/dL with a mean cell haemoglobin of 22.6pg and a mean cell volume of 69.9fl. His peripheral blood smear showed features of thalassaemia intermedia. Haemoglobin (Hb) analysis revealed markedly raised Hb F (83%), normal HbA2 levels and absent HbA. Deoxyribonucleic acid (DNA) analysis showed compound heterozygous IVS1-1 (G→T) β-globin gene mutation and Siriraj I Gγ(Aγδβ)0-deletion (genotype βIVS1-1/ β Siriraj I deletion). Both his father and elder sister are carriers of Siriraj I Gγ(Aγδβ)0-thalassaemia while his mother carries IVS1-1 (G→T) gene mutation. Clinically, the patient is transfusion dependent on six weekly regime. To the best of our knowledge, this is the first reported case in Malaysia involving unique Siriraj I Gγ(Aγδβ)0-thalassaemia and IVS1-1 (G→T) in a compound heterozygous state. In summary, detection of Siriraj I Gγ(Aγδβ)0-thalassaemia is essential as this deletion can lead to severe disease upon interaction with a β-thalassemia point mutation as demonstrated in our case. The establishment of effective carrier screening and genetic counselling is important to prevent its adverse consequences.
    Matched MeSH terms: Heterozygote
  18. Simulation on the roles of the number of quantum well and doping in Inx Ga1-xN multiple quantum wells LEDs
    Zainal N, Azimah E, Hassan Z, Abu Hassan H, Hashim M
    Sains Malaysiana, 2014;43:1557-1564.
    In this work, the emission efficiency of InxGa1-xN based light emitting diodes (LEDs) had been numerically investigated with the variation of the number of quantum well. From our calculation, we found that non-uniformity of carriers distribution (especially electron) in the wells leads to serious inhomogeneity of radiative recombination distribution that would degrade the efficiency of the LED with more wells. However, the problem was minimized when the selected quantum barriers were doped with a reasonable doping level. Comparison with other reported experimental works were also included. At the end of this work, we proposed several types of preferable LEDs designs with optimum structural parameters.
    Matched MeSH terms: Heterozygote
  19. Sickle cell anemia associated with alpha-thalassemia in Malaysian Indians
    Lie-Injo LE, Hassan K, Joishy SK, Lim ML
    Am J Hematol, 1986 Jul;22(3):265-74.
    PMID: 2424302
    The Indian rubber estate workers in Negri Sembilan, Malaysia, who originated from Orissa in India were found to have a high frequency of Hb S (Joishy SK, Hassan K: Clin Res 28:280, 1980). Unlike the usually severe clinical picture of sickle cell anemia seen in African and American blacks, the clinical picture of the disease in this population was mild and many have reached old age. We studied the leukocyte DNA of 12 patients with sickle cell anemia, ranging in age from 4 to 61 years and 30 sickle cell trait carriers, ranging in age from 7 to 63 years, for the presence of alpha-globin gene deletions by gene mapping according to Southern (Southern EM: J Mol Biol 98:503, 1975), using alpha- and zeta-globin gene probes obtained by nick translation of the alpha- and zeta-globin genes cloned into plasmid. All 12 sickle cell anemia patients were found to have alpha-thalassemia2 (alpha-thal2), either in the homozygous or heterozygous condition. Of the Hb S trait carriers, six did not have alpha-thal2 or alpha-thal1 and 24 had alpha-thal2 (15 heterozygous, 9 homozygous). Seven of these Hb S trait carriers with alpha-thal2 had an additional gene abnormality. Five of them had a fast-moving Eco RI fragment 5.6 kb long that hybridized with zeta-specific probe but not with alpha-specific probe. An unusual DNA pattern of a different type was further found in the other two. Bgl II restriction analysis showed that the alpha-thal2 was mostly of the rightward deletion alpha-thal1 genotype. None of the sickle cell anemia patients and Hb S trait carriers had deletion type alpha-thal1. The sickle cell anemia patients had very high levels of Hb F and low levels of Hb A2. The Hb S trait carriers with alpha-thal2 had relatively low levels of Hb S.
    Matched MeSH terms: Heterozygote
  20. Fulltext Semiquantitative screening test for G6PD deficiency detects severe deficiency but misses a substantial proportion of partially-deficient females
    Ainoon O, Alawiyah A, Yu YH, Cheong SK, Hamidah NH, Boo NY, et al.
    Southeast Asian J. Trop. Med. Public Health, 2003 Jun;34(2):405-14.
    PMID: 12971572
    Neonatal screening for G6PD deficiency has long been established in many countries. The aim of the study was to determine whether the routine semiquantitative fluorescent spot test could detect all cases of G6PD deficiency, including those cases with partial deficiency (residual red cell G6PD activity between 20-60% of normal). We compared the results of G6PD screening by the semiquantitative fluorescent spot test and quantitative G6PD activity assay on a group of 976 neonates and 67 known female heterozygotes. The values for mean G6PD activity of G6PD-normal neonates and 293 healthy adult females were determined. There was no significant difference in the mean normal G6PD activity between the two racial groups in the neonates (669 Malays, 307 Chinese) and in the 293 healthy adult females (150 Malays, 143 Chinese) group. The values for the upper limits of total deficiency (20% of normal residual activity) for neonates and adult females were 2.92 U/gHb and 1.54 U/gHb, respectively. The upper limits of partial deficiency (60% of normal residual activity) were 8.7 U/gHb and 4.6 U/gHb respectively. The prevalence of G6PD deficiency among the male neonates was 5.1% (26) by both the fluorescent spot test and the enzyme assay method. The G6PD activity levels of all 26 cases of G6PD-deficient male neonates were < 20% normal (severe enzyme deficiency). In the female neonate group, the frequency of G6PD deficiency was 1.3% (6 of 472) by the fluorescent spot test and 9.35% (44 of 472) by enzyme assay. The 6 cases diagnosed as deficient by the fluorescent spot test showed severe enzyme deficiency (< 2.92 U/gHb). The remaining 38 female neonates had partial enzyme deficiency and all were misdiagnosed as normal by the fluorescent spot test. In the female heterozygote group, G6PD deficiency was diagnosed in 53% (35 of 67) by enzyme assay and in 7.5% (4 of 67) of cases by the fluorescent spot test. The 4 cases detected by fluorescent spot test had severe enzyme deficiency (<1.6 U/gHb). The remaining 31 (46.3%) cases, diagnosed as normal by fluorescent spot test, showed partial G6PD deficiency. In conclusion, we found that the semiquantitative fluorescent spot test could only diagnose cases of total G6PD deficiency and misclassified the partially-deficient cases as normal. In this study, the overall prevalence of G6PD deficiency was 3.28% by the semiquantitative fluorescent spot test and 7.17% by enzyme assay. This means that 3.9% of G6PD-deficient neonates were missed by the routine fluorescent spot test and they were found to be exclusively females. This study demonstrates a need to use a method that can correctly classify female heterozygotes with partial G6PD deficiency. The clinical implication is that these individuals may be at risk of the hemolytic complication of G6PD deficiency.
    Matched MeSH terms: Heterozygote
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