Displaying publications 61 - 80 of 1383 in total

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  1. Hoh BP, Deng L, Julia-Ashazila MJ, Zuraihan Z, Nur-Hasnah M, Nur-Shafawati AR, et al.
    Hum Genomics, 2015 Jul 22;9:16.
    PMID: 26194999 DOI: 10.1186/s40246-015-0039-x
    Fine scale population structure of Malays - the major population in Malaysia, has not been well studied. This may have important implications for both evolutionary and medical studies. Here, we investigated the population sub-structure of Malay involving 431 samples collected from all states from peninsular Malaysia and Singapore. We identified two major clusters of individuals corresponding to the north and south peninsular Malaysia. On an even finer scale, the genetic coordinates of the geographical Malay populations are in correlation with the latitudes (R(2) = 0.3925; P = 0.029). This finding is further supported by the pairwise FST of Malay sub-populations, of which the north and south regions showed the highest differentiation (FST [North-south] = 0.0011). The collective findings therefore suggest that population sub-structure of Malays are more heterogenous than previously expected even within a small geographical region, possibly due to factors like different genetic origins, geographical isolation, could result in spurious association as demonstrated in our analysis. We suggest that cautions should be taken during the stage of study design or interpreting the association signals in disease mapping studies which are expected to be conducted in Malay population in the near future.
    Matched MeSH terms: Asian Continental Ancestry Group/genetics*
  2. Ho PJ, Khng AJ, Tan BK, Tan EY, Tan SM, Tan VKM, et al.
    Breast Cancer, 2022 Sep;29(5):869-879.
    PMID: 35543923 DOI: 10.1007/s12282-022-01366-w
    BACKGROUND: Human leukocyte antigen (HLA) genes play critical roles in immune surveillance, an important defence against tumors. Imputing HLA genotypes from existing single-nucleotide polymorphism datasets is low-cost and efficient. We investigate the relevance of the major histocompatibility complex region in breast cancer susceptibility, using imputed class I and II HLA alleles, in 25,484 women of Asian ancestry.

    METHODS: A total of 12,901 breast cancer cases and 12,583 controls from 12 case-control studies were included in our pooled analysis. HLA imputation was performed using SNP2HLA on 10,886 quality-controlled variants within the 15-55 Mb region on chromosome 6. HLA alleles (n = 175) with info scores greater than 0.8 and frequencies greater than 0.01 were included (resolution at two-digit level: 71; four-digit level: 104). We studied the associations between HLA alleles and breast cancer risk using logistic regression, adjusting for population structure and age. Associations between HLA alleles and the risk of subtypes of breast cancer (ER-positive, ER-negative, HER2-positive, HER2-negative, early-stage, and late-stage) were examined.

    RESULTS: We did not observe associations between any HLA allele and breast cancer risk at P Asian study. Direct measurement of HLA gene expressions may be required to further explore the associations between HLA genes and breast cancer risk.

    Matched MeSH terms: Asian Continental Ancestry Group/genetics
  3. Zilfalil BA, Sarina S, Liza-Sharmini AT, Oldfield NJ, Stenhouse SA
    Singapore Med J, 2006 Feb;47(2):129-33.
    PMID: 16435054
    Cystic fibrosis (CF) is one of the common genetic disorders in the western world. It has been reported to be very rare in Asian populations. According to the Cystic Fibrosis Genetic Analysis Consortium, more than 1,000 mutations of the CF gene have been identified. The CF gene, named the cystic fibrosis transmembrane conductance regulator (CFTR), is located on chromosome 7 and composed of 27 exons. This study aims to detect possible CFTR gene mutations in Malays.
    Matched MeSH terms: Asian Continental Ancestry Group/genetics*
  4. Gunawardena SA, Abeyratne P, Jayasena A, Rajapaksha S, Senadhipathi H, Siriwardana D, et al.
    Sci Justice, 2023 Sep;63(5):638-650.
    PMID: 37718011 DOI: 10.1016/j.scijus.2023.08.001
    Estimating the post mortem interval (PMI) in skeletonized cases is an extremely challenging exercise. Sri Lanka lacks adequate taphonomic research which is a serious limitation when assessing PMI in forensic death investigations. Methods that have been proposed to estimate PMI using the total body score (TBS) and accumulated degree days (ADD) are mainly based on data from continental and temperate climates and have shown less reliability in tropical climates. With the intention of developing a region-specific, evidence-based guide which would be applicable to tropical climates like Sri Lanka, we selected thirteen skeletonized remains with known PMIs from forensic case records and analysed their taphonomy in relation to selected weather data. We also compared the ADD values within our dataset with reference ranges calculated using published formula. All except one were found from outdoor locations. The TBS ranged from 24 to 32 and had a weak positive correlation with the PMI. The earliest appearance of skeletonization was 15 days in a body found indoors. The highest rate of skeletonization was seen in a body with a TBS of 32 and a PMI of 23 days. The average daily temperature and relative humidity were similar across all the cases however, the amount of rainfall varied. Bodies exposed to monsoon rains (n = 6) had a lower mean rate of skeletonization compared to those that were not exposed (n = 4) suggesting lower rates of decomposition during periods of heavy rainfall. No correlation was found between ADD and TBS. In 9 (69.2%) cases, the actual ADD was much lower than reference ADD ranges for TBS values, indicating poor applicability of TBS and ADD based formulae in estimating PMI within the Sri Lankan climate. Our study shows a strong need for taphonomic and entomological research in tropical climates to further explore the impact of monsoons on biotic and abiotic factors affecting skeletonization.
    Matched MeSH terms: Asian Continental Ancestry Group*
  5. Burns-Cox CJ
    Am Heart J, 1970 Nov;80(5):718-9.
    PMID: 5474109
    Matched MeSH terms: Asian Continental Ancestry Group*
  6. Tay YW, Tan AH, Lim JL, Lohmann K, Ibrahim KA, Abdul Aziz Z, et al.
    Parkinsonism Relat Disord, 2023 Jun;111:105399.
    PMID: 37209484 DOI: 10.1016/j.parkreldis.2023.105399
    BACKGROUND: About 5-10% of Parkinson's disease (PD) cases are early onset (EOPD), with several genes implicated, including GBA1, PRKN, PINK1, and SNCA. The spectrum and frequency of mutations vary across populations and globally diverse studies are crucial to comprehensively understand the genetic architecture of PD. The ancestral diversity of Southeast Asians offers opportunities to uncover a rich PD genetics landscape, and identify common regional mutations and new pathogenic variants.

    OBJECTIVES: This study aimed to investigate the genetic architecture of EOPD in a multi-ethnic Malaysian cohort.

    METHODS: 161 index patients with PD onset ≤50 years were recruited from multiple centers across Malaysia. A two-step approach to genetic testing was used, combining a next-generation sequencing-based PD gene panel and multiplex ligation-dependent probe amplification (MLPA).

    RESULTS: Thirty-five patients (21.7%) carried pathogenic or likely pathogenic variants involving (in decreasing order of frequency): GBA1, PRKN, PINK1, DJ-1, LRRK2, and ATP13A2. Pathogenic/likely pathogenic variants in GBA1 were identified in thirteen patients (8.1%), and were also commonly found in PRKN and PINK1 (11/161 = 6.8% and 6/161 = 3.7%, respectively). The overall detection rate was even higher in those with familial history (48.5%) or age of diagnosis ≤40 years (34.8%). PRKN exon 7 deletion and the PINK1 p.Leu347Pro variant appear to be common among Malay patients. Many novel variants were found across the PD-related genes.

    CONCLUSIONS: This study provides novel insights into the genetic architecture of EOPD in Southeast Asians, expands the genetic spectrum in PD-related genes, and highlights the importance of diversifying PD genetic research to include under-represented populations.

    Matched MeSH terms: Asian Continental Ancestry Group/genetics
  7. Deva JP, Ngeow YF, Zin T
    Indian J Ophthalmol, 2023 Jun;71(6):2443-2447.
    PMID: 37322657 DOI: 10.4103/IJO.IJO_2894_22
    PURPOSE: This case-control study aims to examine possible associations of VSX1 exon3 gene variants with the development of keratoconus (KC) in Malaysian patients.

    METHODS: A case-control study was done on 42 keratoconus cases, 127 family member controls, and 96 normal controls.

    RESULTS: Three gene variants, p.A182A, p.P237P, and p.R217H showed significant associations with keratoconus (P < 0.05). While p.A182A and p.P227P were more prevalent than in the family and normal controls (OR 3.14-4.05), the reverse was observed with p.R217H (OR 0.086-1.59). With Haploview analysis, p.A182A and p.P237P were shown to be in linkage disequilibrium (LD) (LOD (logarithm of the odds score) score of 2.0, r2 of 0.957, and 95% confidence interval (CI) of 0.96-1.00).

    CONCLUSION: The study results suggest that the p.A182A and p.P237P variants could have contributed to the development of keratoconus in some Malaysians and that these two variants are likely to be co-inherited. In contrast, the p.R217H variant appeared to confer some protection against the development of keratoconus.

    Matched MeSH terms: Asian Continental Ancestry Group/genetics
  8. Tan YK, Siau CS, Chan LF, Kõlves K, Zhang J, Ho MC, et al.
    Asian J Psychiatr, 2023 Nov;89:103772.
    PMID: 37748229 DOI: 10.1016/j.ajp.2023.103772
    This cross-sectional study aimed to validate the Life Events Checklist for DSM-5 (LEC-5) among Malaysian undergraduates (N = 500; mean age = 21.66 ± 1.57), of which 90.4% had ever experienced a lifetime traumatic event. Cronbach's alpha of .87 (95% CI [.86, .89]) and McDonald's omega of .89 (95% CI [.89, .93]) indicated good reliability. Confirmatory factor analysis based on a six-factor structure showed the best fit. The measurement invariance showed that the six-factor structure was similar across sexes. Therefore, the Malay LEC-5 is a valid and reliable instrument to screen for traumatic events among Malaysian undergraduates.
    Matched MeSH terms: Asian Continental Ancestry Group*
  9. Ratnasingam J, Lim QH, Chan SP
    Curr Opin Endocrinol Diabetes Obes, 2025 Feb 01;32(1):20-25.
    PMID: 39607025 DOI: 10.1097/MED.0000000000000895
    PURPOSE OF REVIEW: The aim of this article was to review the up-to-date evidence with regards to the unique features of the Type 2 diabetes (T2D) pathophysiology, complications, response to therapy with the possibility of precision medicine guiding therapeutic decision making in Asia.

    RECENT FINDINGS: Asia is the epicenter of diabetes. There have been marked advances with genotyping and phenotyping of the Asian patient with T2D, particularly with young onset diabetes where early beta cell failure and rapid progression of complications are more frequent. As Asians have lower muscle mass and higher adiposity, sarcopenia is increasingly associated with diabetes. Response to lifestyle and pharmacotherapy are generally similar, but unique features exist with different populations. Across Asia, use of guideline directed medical therapy for cardio-renal protection are recommended, but uptake of these newer agents are suboptimal and barriers exist with regards to standardized care.

    SUMMARY: Although many similarities have been observed across Asia, due to the heterogeneity of populations within Asia, further research is required to streamline and pave the way towards precision medicine. There is an urgent need for region wide consensus to minimize barriers to diabetes care and stigma in diabetes terminology across Asia.

    Matched MeSH terms: Asian Continental Ancestry Group*
  10. Edgar S, Zulhairy-Liong NA, Ellis M, Trivedi S, Zhu D, Odongo JO, et al.
    Neurogenetics, 2025 Jan 13;26(1):19.
    PMID: 39804470 DOI: 10.1007/s10048-024-00798-0
    Intermediate CAG repeats from 29 to 33 in the ATXN2 gene contributes to the risk of amyotrophic lateral sclerosis (ALS) in European and Asian populations. In this study, 148 ALS patients of multiethnic descent: Chinese (56.1%), Malay (24.3%), Indian (12.8%), others (6.8%) and 100 neurologically normal controls were screened for the ATXN2 CAG repeat expansion. The most common repeat length in both the controls and patients was 22. No familial ALS patients were positive for the intermediate repeat sizes (29-33), while four sporadic patients (2.8%) were positive, with one harbouring a rare ATXN2 homozygous 32 repeat expansion, and a likely pathogenic variant in SPAST. All four patients had limb-onset ALS. Despite representing the smallest ethnic group in our patient cohort, three of the four patients with intermediate repeat sizes were of Indian ancestry. This study, which is the first in Malaysia and Southeast Asia, shows that ATXN2 intermediate risk expansions are relevant to ALS in these populations and will help to inform future genetic testing strategies in the clinic.
    Matched MeSH terms: Asian Continental Ancestry Group/genetics
  11. Wu CH, McCloskey EV, Lee JK, Itabashi A, Prince R, Yu W, et al.
    J Clin Densitom, 2014;17(1):150-5.
    PMID: 23916756 DOI: 10.1016/j.jocd.2013.06.002
    The fracture risk assessment tool (FRAX(®)) has been developed for the identification of individuals with high risk of fracture in whom treatment to prevent fractures would be appropriate. FRAX models are not yet available for all countries or ethnicities, but surrogate models can be used within regions with similar fracture risk. The International Society for Clinical Densitometry (ISCD) and International Osteoporosis Foundation (IOF) are nonprofit multidisciplinary international professional organizations. Their visions are to advance the awareness, education, prevention, and treatment of osteoporosis. In November 2010, the IOF/ISCD FRAX initiative was held in Bucharest, bringing together international experts to review and create evidence-based official positions guiding clinicians for the practical use of FRAX. A consensus meeting of the Asia-Pacific (AP) Panel of the ISCD recently reviewed the most current Official Positions of the Joint Official Positions of ISCD and IOF on FRAX in view of the different population characteristics and health standards in the AP regions. The reviewed position statements included not only the key spectrum of positions but also unique concerns in AP regions.
    Matched MeSH terms: Asian Continental Ancestry Group*
  12. Minaguchi K, Samejima M, Nambiar P, Kaneko Y, Ochiai E, Kakimoto Y, et al.
    Leg Med (Tokyo), 2024 Sep;70:102463.
    PMID: 38823287 DOI: 10.1016/j.legalmed.2024.102463
    Closely linked groups of markers on the X chromosome are very useful for testing complex kinship relationships involving X-STR transmission. The Argus X-12 kit, a unique commercially available kit, can obtain haplotypes of 4 linkage groups (LGs) consisting of 3 markers. Although many population data have been reported for forensic purposes, differences in discrimination ability exist between LG1 and LG2, 3, and 4 in East Asian populations, and the data of this kit would become more useful if the discrimination ability of the latter groups were increased. Therefore, for matches found using this kit for some linkage group data, then to increase the identification ability, we additionally introduced 13 X-STR loci and established a method allowing comparison using data from 25 loci. The 13X-STRs add two locus data to each of LG2, 3, and 4, and also add two closely linked group (CLG) data between LG2 and 3 and LG3 and 4 in one multiplex PCR. Assessment of this method for a Malay population for which data by Argus X-12 had already been reported showed that the frequencies of distinct haplotypes in LG2, 3, and 4 were increased by 33.0-42.6 %, and frequencies of unique haplotypes increased by 45.4-59.2 %. The respective haplotype diversity values of the additional 3-locus and 4-locus CLGs were 0.9838 and 0.9939, which helps to improve discriminatory power and to predict recombination locations on the X chromosome. Although we have been testing these loci with Japanese subjects, this system would also be useful for the Malay population.
    Matched MeSH terms: Asian Continental Ancestry Group/genetics
  13. Wise CA, Sullivan SG, Black ML, Erber WN, Bittles AH
    Am J Phys Anthropol, 2005 Nov;128(3):670-7.
    PMID: 15864813
    Christmas Island is a remote Australian territory located close to the main Indonesian island of Java. Y-chromosome and mitochondrial DNA (mtDNA) markers were used to investigate the genetic structure of the population, which comprises communities of mixed ethnic origin. Analysis of 12 Y-chromosome biallelic polymorphisms revealed a high level of gene diversity and haplotype frequencies that were consistent with source populations in southern China and Southeast Asia. mtDNA hypervariable segment I (HVS-I) sequences displayed high levels of haplotype diversity and nucleotide diversity that were comparable to various Asian populations. Genetic distances revealed extremely low mtDNA differentiation among Christmas Islanders and Asian populations. This was supported by the relatively high proportion of sequence types shared among these populations. The most common mtDNA haplogroups were M* and B, followed by D and F, which are prevalent in East/Southeast Asia. Christmas Islanders of European descent were characterized by the Eurasian haplogroup R*, and a limited degree of admixture was observed. In general, analysis of the genetic data indicated population affinities to southern Chinese (in particular from the Yunnan Province) and Southeast Asia (Thailand, Malaysia, and Cambodia), which was consistent with historical records of settlement. The combined use of these different marker systems provides a useful and appropriate model for the study of contemporary populations derived from different ethnic origins.
    Matched MeSH terms: Asian Continental Ancestry Group/genetics
  14. Chen KH, Cann H, Chen TC, Van West B, Cavalli-Sforza L
    Am J Phys Anthropol, 1985 Mar;66(3):327-37.
    PMID: 3857010
    A group of Taiwan aborigines, the Toroko, was typed for 21 classical genetic loci. This is part of an ongoing program aimed at a comprehensive study of Taiwan aborigines. In this first paper a short summary of historical, archeological, and anthropological data in the literature is made, and results of the present survey are compared with older results from other aborigine tribes. An analysis of other neighboring populations from southeast Asia has also been carried out in order to give a preliminary answer to the question of origin of Taiwanese aborigines. Fifteen populations were studied for 13 loci by tree analysis, principal components, and isolation by distance. Tree analysis and principal component analysis gave results in fairly good agreement and indicate three major population clusters: a northeast cluster (Ainu, Korea, Japan, and Ryukyu); a southeast cluster (south China, Thailand, Vietnam, Philippines, Taiwan, and Toroko); and a third cluster including Malaya and Borneo. The positions of Polynesia, Micronesia, and Melanesia are somewhat peripheral. Analysis of the tree shows some potential cases of convergence, perhaps owing to admixture, and of divergence. The analysis of isolation by distance shows that geographic propinquity is a reasonably good predictor of general similarity in this area.
    Matched MeSH terms: Asian Continental Ancestry Group*
  15. Lye TP
    Hum Biol, 2013 Feb-Jun;85(1-3):417-44.
    PMID: 24297236 DOI: 10.3378/027.085.0320
    The so-called negritos adapt not just to a tropical forest environment but also to an environment characterized by perturbations and fluctuations. As with other hunter-gatherers in the region and, indeed, throughout the world, they use both social and ecological methods to enhance their chances of survival in this changing environment: socially, they have developed networks of trading and marriage partners; ecologically, they maintain patches of key resources that are available for future harvesting. As evidenced in the case of the Batek (Orang Asli), patterns of forest structure and composition are sometimes direct outcomes of intentional resource concentration and enrichment strategies. While little of the above is controversial anthropologically, what has drawn some debate is the nature of the relationship with partner societies. Conventional wisdom posits relations of inequality between foragers and "others": foragers and farmers are often construed as hierarchical dyads where foragers supply products or labor to farmers in exchange for agricultural harvests and other trade goods. This kind of adaptation appears to be one of divergent specialization. However, there are cases, such as in the relationship between Batek and Semaq Beri, where both societies follow a roughly similar mode of adaptation, and specialization has not materialized. In sum, while not denying that hierarchy and inequality exist, I suggest that they have to be contextualized within a larger strand of relationships that includes both hierarchy and egality. Further, such relationships are part of the general portfolio of risk reduction strategies, following which access to widely scattered environmental resources, and passage from one location to another, is enhanced not by competing with and displacing neighbors but by maintaining a flexible regime of friendly exchange partners.
    Matched MeSH terms: Asian Continental Ancestry Group*
  16. Blust R
    Hum Biol, 2013 Feb-Jun;85(1-3):401-16.
    PMID: 24297235
    Within recorded history, most Southeast Asian peoples have been of "southern Mongoloid" physical type, whether they speak Austroasiatic, Tibeto-Burman, Austronesian, Tai-Kadai, or Hmong-Mien languages. However, population distributions suggest that this is a post-Pleistocene phenomenon and that for tens of millennia before the last glaciation ended Greater Mainland Southeast Asia, which included the currently insular world that rests on the Sunda Shelf, was peopled by short, dark-skinned, frizzy-haired foragers whose descendants in the Philippines came to be labeled by the sixteenth-century Spanish colonizers as "negritos," a term that has since been extended to similar groups throughout the region. There are three areas in which these populations survived into the present so as to become part of written history: the Philippines, the Malay Peninsula, and the Andaman Islands. All Philippine negritos speak Austronesian languages, and all Malayan negritos speak languages in the nuclear Mon-Khmer branch of Austroasiatic, but the linguistic situation in the Andamans is a world apart. Given prehistoric language shifts among both Philippine and Malayan negritos, the prospects of determining whether disparate negrito populations were once a linguistically or culturally unified community would appear hopeless. Surprisingly, however, some clues to a common negrito past do survive in a most unexpected way.
    Matched MeSH terms: Asian Continental Ancestry Group*
  17. Dunn M, Kruspe N, Burenhult N
    Hum Biol, 2013 Feb-Jun;85(1-3):383-400.
    PMID: 24297234
    The Aslian language family, located in the Malay Peninsula and southern Thai Isthmus, consists of four distinct branches comprising some 18 languages. These languages predate the now dominant Malay and Thai. The speakers of Aslian languages exhibit some of the highest degree of phylogenetic and societal diversity present in Mainland Southeast Asia today, among them a foraging tradition particularly associated with locally ancient, Pleistocene genetic lineages. Little advance has been made in our understanding of the linguistic prehistory of this region or how such complexity arose. In this article we present a Bayesian phylogeographic analysis of a large sample of Aslian languages. An explicit geographic model of diffusion is combined with a cognate birth-word death model of lexical evolution to infer the location of the major events of Aslian cladogenesis. The resultant phylogenetic trees are calibrated against dates in the historical and archaeological record to infer a detailed picture of Aslian language history, addressing a number of outstanding questions, including (1) whether the root ancestor of Aslian was spoken in the Malay Peninsula, or whether the family had already divided before entry, and (2) the dynamics of the movement of Aslian languages across the peninsula, with a particular focus on its spread to the indigenous foragers.
    Matched MeSH terms: Asian Continental Ancestry Group/ethnology*
  18. Ragu R, Eng JY, Azlina AR
    Med J Malaysia, 2014 Aug;69(4):199-201.
    PMID: 25500854
    Kimura's disease is rare chronic inflammatory disease with a distinct clinicopathological entity. It has three major components; inflammatory, vascular and fibrosis. It has to be considered as a differential diagnosis in young patient presenting with head and neck swelling. Although of unknown aetiology many hypothesis has been postulated. Inflammation is the most prominent and predominating characteristic in this disease. Although reported to be predominant in Asian literature regarding this disease is scanty. We report a complete clinical-radiological and pathological picture of this disease.
    Matched MeSH terms: Asian Continental Ancestry Group
  19. Konto M, Fufa GI, Zakaria A, Tukur SM, Watanabe M, Ola-Fadunsin SD, et al.
    Vet World, 2015 Oct;8(10):1167-71.
    PMID: 27047012 DOI: 10.14202/vetworld.2015.1167-1171
    The red jungle fowl is generally considered as one of the endangered Asian wild Galleopheasants due to man-made encroachment of their habitats, coupled with the effect of disease and disease causing organisms like ticks and tick-borne infections. This study aimed to determine the tick fauna of the red jungle fowl and their predilection sites based on developmental stages.
    Matched MeSH terms: Asian Continental Ancestry Group
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