Displaying publications 101 - 116 of 116 in total

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  1. Iwai K, Hirono A, Matsuoka H, Kawamoto F, Horie T, Lin K, et al.
    Hum Genet, 2001 Jun;108(6):445-9.
    PMID: 11499668
    Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a heterogeneous enzyme abnormality with high frequency in tropical areas. We performed population screening and molecular studies of G6PD variants to clarify their distribution and features in Southeast Asia. A total of 4317 participants (2019 males, 2298 females) from 16 ethnic groups in Myanmar, Lao in Laos, and Amboinese in Indonesia were screened with a single-step screening method. The prevalence of G6PD-deficient males ranged from 0% (the Akha) to 10.8% (the Shan). These G6PD-deficient individuals and 12 G6PD-deficient patients who had been diagnosed at hospitals in Indonesia and Malaysia were subjected to molecular analysis by a combination of polymerase-chain-reaction-based single-strand conformation polymorphism analysis and direct sequencing. Ten different missense mutations were identified in 63 G6PD-deficient individuals (50 hemizygotes, 11 heterozygotes, and 2 homozygotes) from 14 ethnic groups. One missense mutation (1291 G-->A) found in an Indonesian Chinese, viz., G6PD Surabaya, was previously unknown. The 487 G-->A (G6PD Mahidol) mutation was widely seen in Myanmar, 383 T-->C (G6PD Vanua Lava) was specifically found among Amboinese, 871 G-->A (G6PD Viangchan) was observed mainly in Lao, and 592 C-->T (G6PD Coimbra) was found in Malaysian aborigines (Orang Asli). The other five mutations, 95 A-->G (G6PD Gaohe), 1003 G-->A (G6PD Chatham), 1360 C-->T (G6PD Union), 1376 G-->T (G6PD Canton), and 1388 G-->A (G6PD Kaiping) were identified mostly in accordance with distributions reported previously.
    Matched MeSH terms: Genetic Testing
  2. 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: Genetic Testing
  3. Leung D, Chua GT, Mondragon AV, Zhong Y, Nguyen-Ngoc-Quynh L, Imai K, et al.
    Front Immunol, 2020;11:1605.
    PMID: 32903579 DOI: 10.3389/fimmu.2020.01605
    Background: The Asia Pacific Society for Immunodeficiencies (APSID) conducted nine primary immunodeficiency (PID) Schools in 5 years since inauguration to provide PID care training for early career physicians in Asia Pacific, a region with divergent needs in PID resources and training. Objective: To identify differences in PID patient care resource and training needs across Asia Pacific and propose a corresponding action plan. Methods: The Human Development Index (HDI) indicates the degree of socio-economic development in each country/region. Information related to investigations and learning issues were extracted from the abstracts and personal statements from all Schools and mapped onto resource and training needs. Correlations between HDI and country/region-specific parameters were tested by two-tailed Pearson correlation. Results: A total of 427 abstracts were received in nine Schools between 2015 and 2020, predominantly on immunodeficiencies affecting cellular and humoral immunity. Genetic confirmation was described in 61.8% of abstracts, and its absence negatively correlated with HDI (r = -0.696, p = 0.004). Essential immunologic and genetic tests were not available in 25.4 and 29.5% of abstracts, respectively, and their absence negatively correlated with HDI (r = -0.788, p < 0.001; r = -0.739, p = 0.002). HDI positively correlated with average testing level (r = 0.742, p = 0.002). Cases from medium-HDI countries/regions focused on learning how to investigate a patient for PIDs in cases of severe or atypical infections, whereas those from very-high-HDI countries/regions, from which most faculty members originated, listed hematopoietic stem cell transplantation and gene therapy, newborn screening, and research as learning issues more frequently. Conclusion: There are unique HDI-related PID resource and training needs in each country/region. APSID proposes HDI group-specific strategies to improve PID care and education in her member countries/regions. Further quantitative analysis of needs in PID care in Asia Pacific is needed for lobbying governments to increase their support for PID care and research.
    Matched MeSH terms: Genetic Testing
  4. Yahya N, Chua XJ, Manan HA, Ismail F
    Strahlenther Onkol, 2018 08;194(8):780-786.
    PMID: 29774397 DOI: 10.1007/s00066-018-1303-5
    PURPOSE: This systematic review evaluates the completeness of dosimetric features and their inclusion as covariates in genetic-toxicity association studies.

    MATERIALS AND METHODS: Original research studies associating genetic features and normal tissue complications following radiotherapy were identified from PubMed. The use of dosimetric data was determined by mining the statement of prescription dose, dose fractionation, target volume selection or arrangement and dose distribution. The consideration of the dosimetric data as covariates was based on the statement mentioned in the statistical analysis section. The significance of these covariates was extracted from the results section. Descriptive analyses were performed to determine their completeness and inclusion as covariates.

    RESULTS: A total of 174 studies were found to satisfy the inclusion criteria. Studies published ≥2010 showed increased use of dose distribution information (p = 0.07). 33% of studies did not include any dose features in the analysis of gene-toxicity associations. Only 29% included dose distribution features as covariates and reported the results. 59% of studies which included dose distribution features found significant associations to toxicity.

    CONCLUSION: A large proportion of studies on the correlation of genetic markers with radiotherapy-related side effects considered no dosimetric parameters. Significance of dose distribution features was found in more than half of the studies including these features, emphasizing their importance. Completeness of radiation-specific clinical data may have increased in recent years which may improve gene-toxicity association studies.

    Matched MeSH terms: Genetic Testing
  5. El-Desouky S, Taalab YM, El-Gamal M, Mohamed W, Salama M
    Methods Mol Biol, 2019;2011:451-464.
    PMID: 31273716 DOI: 10.1007/978-1-4939-9554-7_27
    Leigh syndrome (LS) is a common neurodegenerative disease affecting neonates with devastating sequences. One of the characteristic features for LS is the phenotypic polymorphism, which-in part-can be dedicated to variety of genetic causes. A strong correlation with mitochondrial dysfunction has been assumed as the main cause of LS. This was based on the fact that most genetic causes are related to mitochondrial complex I genome. The first animal LS model was designed based on NDUFS4 knockdown. Interestingly, however, this one or others could not recapitulate the whole spectrum of manifestations encountered in different cases of LS. We show in this chapter a new animal model for LS based on silencing of one gene that is reported previously in clinical cases, FOXRED1. The new model carries some differences from previous models in the fact that more histopathological degeneration in dopaminergic system is seen and more behavioral changes can be recognized. FOXRED1 is an interesting gene that is related to complex I assembly, hence, plays important role in different neurodegenerative disorders leading to different clinical manifestations.
    Matched MeSH terms: Genetic Testing
  6. Barlow-Stewart K, Yeo SS, Meiser B, Goldstein D, Tucker K, Eisenbruch M
    Genet Med, 2006 Jan;8(1):24-32.
    PMID: 16418596
    PURPOSE: In societies such as Australia with a strong multicultural makeup, culturally determined attitudes to genetics, testing, and counseling may be incompatible with current genetics service provision.

    METHODS: An ethnographic investigation using purposive sampling to increase subject diversity was used to explore the range of beliefs about kinship and inheritance using Chinese-Australians as a case. Participants comprised a sample of 15 Chinese-Australians who had been recruited through several community-based organizations.

    RESULTS: The level of acculturation does not correlate with holding beliefs about inheritance, kinship, and causes of hereditary cancer that are based on "Western" biomedical or traditional concepts. Mismatch between beliefs may exist within families that can impact participation in cancer genetic testing. Family history taking that underpins the surveillance, management, and referral to genetic counseling where there is a strong family history of breast, ovarian, or colorectal cancer can also be impacted unless recognition is made of the patrilineal concept of kinship prevalent in this Chinese-Australian community.

    CONCLUSION: This community-based study confirmed and validated views and beliefs on inheritance and kinship and inherited cancer attributed to senior family members by Chinese-Australians who attended cancer genetic counseling. Barriers to communication can occur where there may be incompatibility within the family between "Western" and traditional beliefs. The findings were used to develop strategies for culturally competent cancer genetic counseling with Australian-Chinese patients. These include nonjudgmental incorporation of their belief systems into the genetic counseling process and avoidance of stereotyping. They have also influenced the development of genetics education materials to optimize family history taking.

    Matched MeSH terms: Genetic Testing
  7. Shahrizaila N, Samulong S, Tey S, Suan LC, Meng LK, Goh KJ, et al.
    Muscle Nerve, 2014 Feb;49(2):198-201.
    PMID: 23649551 DOI: 10.1002/mus.23892
    Data regarding Charcot-Marie-Tooth disease is lacking in Southeast Asian populations. We investigated the frequency of the common genetic mutations in a multiethnic Malaysian cohort.
    Matched MeSH terms: Genetic Testing
  8. Lee DS, Yoon SY, Looi LM, Kang P, Kang IN, Sivanandan K, et al.
    Breast Cancer Res, 2012;14(2):R66.
    PMID: 22507745
    Germline TP53 mutations cause an increased risk to early-onset breast cancer in Li-Fraumeni syndrome (LFS) families and the majority of carriers identified through breast cancer cohorts have LFS or Li-Fraumeni-like (LFL) features. However, in Asia and in many low resource settings, it is challenging to obtain accurate family history and we, therefore, sought to determine whether the presence of early-onset breast cancer is an appropriate selection criteria for germline TP53 testing.
    Matched MeSH terms: Genetic Testing
  9. Kang PC, Phuah SY, Sivanandan K, Kang IN, Thirthagiri E, Liu JJ, et al.
    Breast Cancer Res Treat, 2014 Apr;144(3):635-42.
    PMID: 24578176 DOI: 10.1007/s10549-014-2894-x
    Although the breast cancer predisposition genes BRCA1 and BRCA2 were discovered more than 20 years ago, there remains a gap in the availability of genetic counselling and genetic testing in Asian countries because of cost, access and inaccurate reporting of family history of cancer. In order to improve access to testing, we developed a rapid test for recurrent mutations in our Asian populations. In this study, we designed a genotyping assay with 55 BRCA1 and 44 BRCA2 mutations previously identified in Asian studies, and validated this assay in 267 individuals who had previously been tested by full sequencing. We tested the prevalence of these mutations in additional breast cancer cases. Using this genotyping approach, we analysed recurrent mutations in 533 Malaysian breast cancer cases with <10 % a priori risk, and found 1 BRCA1 (0.2 %) and 5 BRCA2 (0.9 %) carriers. Testing in a hospital-based unselected cohort of 532 Singaporean breast cancer cases revealed 6 BRCA1 (1.1 %) and 3 BRCA2 (0.6 %) carriers. Overall, 2 recurrent BRCA1 and 1 BRCA2 mutations in Malays, 3 BRCA1 and 2 BRCA2 mutations in Chinese and 1 BRCA1 mutation in Indians account for 60, 24 and 20 % of carrier families, respectively. By contrast, haplotype analyses suggest that a recurrent BRCA2 mutation (c.262_263delCT) found in 5 unrelated Malay families has at least 3 distinct haplotypes. Taken together, our data suggests that panel testing may help to identify carriers, particularly Asian BRCA2 carriers, who do not present with a priori strong family history characteristics.
    Matched MeSH terms: Genetic Testing
  10. 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: Genetic Testing
  11. Valli H, Ahmad S, Fraser JA, Jeevaratnam K, Huang CL
    Exp Physiol, 2017 12 01;102(12):1619-1634.
    PMID: 28960529 DOI: 10.1113/EP086589
    NEW FINDINGS: What is the central question of this study? Can we experimentally replicate atrial pro-arrhythmic phenotypes associated with important chronic clinical conditions, including physical inactivity, obesity, diabetes mellitus and metabolic syndrome, compromising mitochondrial function, and clarify their electrophysiological basis? What is the main finding and its importance? Electrocardiographic and intracellular cardiomyocyte recording at progressively incremented pacing rates demonstrated age-dependent atrial arrhythmic phenotypes in Langendorff-perfused murine Pgc1β-/- hearts for the first time. We attributed these to compromised action potential conduction and excitation wavefronts, whilst excluding alterations in recovery properties or temporal electrophysiological instabilities, clarifying these pro-arrhythmic changes in chronic metabolic disease. Atrial arrhythmias, most commonly manifesting as atrial fibrillation, represent a major clinical problem. The incidence of atrial fibrillation increases with both age and conditions associated with energetic dysfunction. Atrial arrhythmic phenotypes were compared in young (12-16 week) and aged (>52 week) wild-type (WT) and peroxisome proliferative activated receptor, gamma, coactivator 1 beta (Ppargc1b)-deficient (Pgc1β-/- ) Langendorff-perfused hearts, previously used to model mitochondrial energetic disorder. Electrophysiological explorations were performed using simultaneous whole-heart ECG and intracellular atrial action potential (AP) recordings. Two stimulation protocols were used: an S1S2 protocol, which imposed extrasystolic stimuli at successively decremented intervals following regular pulse trains; and a regular pacing protocol at successively incremented frequencies. Aged Pgc1β-/- hearts showed greater atrial arrhythmogenicity, presenting as atrial tachycardia and ectopic activity. Maximal rates of AP depolarization (dV/dtmax ) were reduced in Pgc1β-/- hearts. Action potential latencies were increased by the Pgc1β-/- genotype, with an added interactive effect of age. In contrast, AP durations to 90% recovery (APD90 ) were shorter in Pgc1β-/- hearts despite similar atrial effective recovery periods amongst the different groups. These findings accompanied paradoxical decreases in the incidence and duration of alternans in the aged and Pgc1β-/- hearts. Limiting slopes of restitution curves of APD90 against diastolic interval were correspondingly reduced interactively by Pgc1β-/- genotype and age. In contrast, reduced AP wavelengths were associated with Pgc1β-/- genotype, both independently and interacting with age, through the basic cycle lengths explored, with the aged Pgc1β-/- hearts showing the shortest wavelengths. These findings thus implicate AP wavelength in possible mechanisms for the atrial arrhythmic changes reported here.
    Matched MeSH terms: Genetic Testing
  12. Lecarpentier J, Silvestri V, Kuchenbaecker KB, Barrowdale D, Dennis J, McGuffog L, et al.
    J Clin Oncol, 2017 Jul 10;35(20):2240-2250.
    PMID: 28448241 DOI: 10.1200/JCO.2016.69.4935
    Purpose BRCA1/2 mutations increase the risk of breast and prostate cancer in men. Common genetic variants modify cancer risks for female carriers of BRCA1/2 mutations. We investigated-for the first time to our knowledge-associations of common genetic variants with breast and prostate cancer risks for male carriers of BRCA1/ 2 mutations and implications for cancer risk prediction. Materials and Methods We genotyped 1,802 male carriers of BRCA1/2 mutations from the Consortium of Investigators of Modifiers of BRCA1/2 by using the custom Illumina OncoArray. We investigated the combined effects of established breast and prostate cancer susceptibility variants on cancer risks for male carriers of BRCA1/2 mutations by constructing weighted polygenic risk scores (PRSs) using published effect estimates as weights. Results In male carriers of BRCA1/2 mutations, PRS that was based on 88 female breast cancer susceptibility variants was associated with breast cancer risk (odds ratio per standard deviation of PRS, 1.36; 95% CI, 1.19 to 1.56; P = 8.6 × 10-6). Similarly, PRS that was based on 103 prostate cancer susceptibility variants was associated with prostate cancer risk (odds ratio per SD of PRS, 1.56; 95% CI, 1.35 to 1.81; P = 3.2 × 10-9). Large differences in absolute cancer risks were observed at the extremes of the PRS distribution. For example, prostate cancer risk by age 80 years at the 5th and 95th percentiles of the PRS varies from 7% to 26% for carriers of BRCA1 mutations and from 19% to 61% for carriers of BRCA2 mutations, respectively. Conclusion PRSs may provide informative cancer risk stratification for male carriers of BRCA1/2 mutations that might enable these men and their physicians to make informed decisions on the type and timing of breast and prostate cancer risk management.
    Matched MeSH terms: Genetic Testing
  13. Gavriilaki E, Asteris PG, Touloumenidou T, Koravou EE, Koutra M, Papayanni PG, et al.
    Clin Immunol, 2021 May;226:108726.
    PMID: 33845193 DOI: 10.1016/j.clim.2021.108726
    Recent studies suggest excessive complement activation in severe coronavirus disease-19 (COVID-19). The latter shares common characteristics with complement-mediated thrombotic microangiopathy (TMA). We hypothesized that genetic susceptibility would be evident in patients with severe COVID-19 (similar to TMA) and associated with disease severity. We analyzed genetic and clinical data from 97 patients hospitalized for COVID-19. Through targeted next-generation-sequencing we found an ADAMTS13 variant in 49 patients, along with two risk factor variants (C3, 21 patients; CFH,34 patients). 31 (32%) patients had a combination of these, which was independently associated with ICU hospitalization (p = 0.022). Analysis of almost infinite variant combinations showed that patients with rs1042580 in thrombomodulin and without rs800292 in complement factor H did not require ICU hospitalization. We also observed gender differences in ADAMTS13 and complement-related variants. In light of encouraging results by complement inhibitors, our study highlights a patient population that might benefit from early initiation of specific treatment.
    Matched MeSH terms: Genetic Testing
  14. Mohd Khalid MK, Yakob Y, Md Yasin R, Wee Teik K, Siew CG, Rahmat J, et al.
    Mol Vis, 2015;21:1185-90.
    PMID: 26539030
    The availability of molecular genetic testing for retinoblastoma (RB) in Malaysia has enabled patients with a heritable predisposition to the disease to be identified, which thus improves the clinical management of these patients and their families. In this paper, we presented our strategy for performing molecular genetic testing of the RB1 gene and the findings from our first 2 years of starting this service.
    Matched MeSH terms: Genetic Testing
  15. Laver TW, Wakeling MN, Hua JHY, Houghton JAL, Hussain K, Ellard S, et al.
    Clin Endocrinol (Oxf), 2018 Nov;89(5):621-627.
    PMID: 30238501 DOI: 10.1111/cen.13841
    OBJECTIVE: Hyperinsulinaemic hypoglycaemia (HH) can occur in isolation or more rarely feature as part of a syndrome. Screening for mutations in the "syndromic" HH genes is guided by phenotype with genetic testing used to confirm the clinical diagnosis. As HH can be the presenting feature of a syndrome, it is possible that mutations will be missed as these genes are not routinely screened in all newly diagnosed individuals. We investigated the frequency of pathogenic variants in syndromic genes in infants with HH who had not been clinically diagnosed with a syndromic disorder at referral for genetic testing.

    DESIGN: We used genome sequencing data to assess the prevalence of mutations in syndromic HH genes in an international cohort of patients with HH of unknown genetic cause.

    PATIENTS: We undertook genome sequencing in 82 infants with HH without a clinical diagnosis of a known syndrome at referral for genetic testing.

    MEASUREMENTS: Within this cohort, we searched for the genetic aetiologies causing 20 different syndromes where HH had been reported as a feature.

    RESULTS: We identified a pathogenic KMT2D variant in a patient with HH diagnosed at birth, confirming a genetic diagnosis of Kabuki syndrome. Clinical data received following the identification of the mutation highlighted additional features consistent with the genetic diagnosis. Pathogenic variants were not identified in the remainder of the cohort.

    CONCLUSIONS: Pathogenic variants in the syndromic HH genes are rare; thus, routine testing of these genes by molecular genetics laboratories is unlikely to be justified in patients without syndromic phenotypes.

    Matched MeSH terms: Genetic Testing
  16. Chen BC, McGown IN, Thong MK, Pitt J, Yunus ZM, Khoo TB, et al.
    J Inherit Metab Dis, 2010 Dec;33 Suppl 3:S159-62.
    PMID: 20177786 DOI: 10.1007/s10545-010-9056-z
    Most cases of adenylosuccinate lyase (ADSL OMIM 103050) deficiency reported to date are confined to the various European ethnic groups. We report on the first Malaysian case of ADSL deficiency, which appears also to be the first reported Asian case. The case was diagnosed among a cohort of 450 patients with clinical features of psychomotor retardation, global developmental delay, seizures, microcephaly and/or autistic behaviour. The patient presented with frequent convulsions and severe myoclonic jerk within the first few days of life and severe psychomotor retardation. The high performance liquid chromatography (HPLC) profile of the urine revealed the characteristic biochemical markers of succinyladenosine (S-Ado) and succinyl-aminoimidazole carboximide riboside (SAICAr). The urinary S-Ado/SAICAr ratio was found to be 1.02 (type I ADSL deficiency). The patient was compound heterozygous for two novel mutations, c.445C > G (p.R149G) and c.774_778insG (p.A260GfsX24).
    Matched MeSH terms: Genetic Testing/methods*
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