The LRRK2 gene has been associated with both familial and sporadic forms of Parkinson's disease (PD). The G2019S variant is commonly found in North African Arab and Caucasian PD patients, but this locus is monomorphic in Asians. The G2385R and R1628P variants are associated with a higher risk of developing PD in certain Asian populations but have not been studied in the Malaysian population. Therefore, we screened the G2385R and R1628P variants in 1,202 Malaysian subjects consisting of 695 cases and 507 controls. The G2385R and R1628P variants were associated with a 2.2-fold (P = 0.019) and 1.2-fold (P = 0.054) increased risk of PD, respectively. Our data concur with other reported findings in Chinese, Taiwanese, Singaporean, and Korean studies.
Matched MeSH terms: Asian Continental Ancestry Group/genetics*
To evaluate the contribution of non-synonymous-coding variants of known familial and genome-wide association studies (GWAS)-linked genes for Parkinson's disease (PD) to PD risk in the East Asian population, we sequenced all the coding exons of 39 PD-related disease genes and evaluated the accumulation of rare non-synonymous-coding variants in 375 early-onset PD cases and 399 controls. We also genotyped 782 non-synonymous-coding variants of these genes in 710 late-onset PD cases and 9046 population controls. Significant enrichment of LRRK2 variants was observed in both early- and late-onset PD (odds ratio = 1.58; 95% confidence interval = 1.29-1.93; P = 8.05 × 10(-6)). Moderate enrichment was also observed in FGF20, MCCC1, GBA and ITGA8. Half of the rare variants anticipated to cause loss of function of these genes were present in healthy controls. Overall, non-synonymous-coding variants of known familial and GWAS-linked genes appear to make a limited contribution to PD risk, suggesting that clinical sequencing of these genes will provide limited information for risk prediction and molecular diagnosis.
Matched MeSH terms: Asian Continental Ancestry Group/genetics*
Tuberous sclerosis complex is an autosomal dominant neurocutaneous disorder affecting multiple organs. Tuberous sclerosis complex is caused by mutation in either one of the two disease-causing genes, TSC1 or TSC2, encoding for hamartin and tuberin, respectively. TSC2/PKD1 contiguous gene deletion syndrome is a very rare condition due to deletion involving both TSC2 and PKD1 genes. Tuberous sclerosis complex cannot be easily diagnosed since there is no pathognomonic feature, although there are consensus diagnostic criteria for that. Mutation analysis is useful and plays important roles. We report here two novel gross deletions of TSC2 gene in Malay patients with tuberous sclerosis complex and TSC2/PKD1 contiguous gene deletion syndrome, respectively.
Matched MeSH terms: Asian Continental Ancestry Group/genetics*
The OPRM1 gene encodes the µ-opioid receptor, which is the primary site of action of most opioids. Several studies and three meta-analyses have examined a possible link between the exonic OPRM1 A118G (rs1799971) polymorphism and opioid dependence; however, results have been inconclusive. Therefore, a systematic review and meta-analysis have been carried out to examine whether this polymorphism is associated with opioid dependence. Thirteen studies (n = 9385), comprising 4601 opioid dependents and 4784 controls, which evaluated association of the OPRM1 rs1799971 polymorphism with susceptibility to opioids, were included in this study. Our meta-analysis showed significant association between this polymorphism and susceptibility to opioid dependence in overall studies under a codominant model, as well as susceptibility to opioid dependence or heroin dependence in Asians under an autosomal dominant model. The nonsynonymous OPRM1 rs1799971 might be a risk factor for addiction to opioids or heroin in an Asian population.
Matched MeSH terms: Asian Continental Ancestry Group/genetics
Hypercholesterolemia is caused by different interactions of lifestyle and genetic determinants. At the genetic level, it can be attributed to the interactions of multiple polymorphisms, or as in the example of familial hypercholesterolemia (FH), it can be the result of a single mutation. A large number of genetic markers, mostly single nucleotide polymorphisms (SNP) or mutations in three genes, implicated in autosomal dominant hypercholesterolemia (ADH), viz APOB (apolipoprotein B), LDLR (low density lipoprotein receptor) and PCSK9 (proprotein convertase subtilisin/kexin type-9), have been identified and characterized. However, such studies have been insufficiently undertaken specifically in Malaysia and Southeast Asia in general. The main objective of this study was to identify ADH variants, specifically ADH-causing mutations and hypercholesterolemia-associated polymorphisms in multiethnic Malaysian population. We aimed to evaluate published SNPs in ADH causing genes, in this population and to report any unusual trends. We examined a large number of selected SNPs from previous studies of APOB, LDLR, PCSK9 and other genes, in clinically diagnosed ADH patients (n=141) and healthy control subjects (n=111). Selection of SNPs was initiated by searching within genes reported to be associated with ADH from known databases. The important finding was 137 mono-allelic markers (44.1%) and 173 polymorphic markers (55.8%) in both subject groups. By comparing to publicly available data, out of the 137 mono-allelic markers, 23 markers showed significant differences in allele frequency among Malaysians, European Whites, Han Chinese, Yoruba and Gujarati Indians. Our data can serve as reference for others in related fields of study during the planning of their experiments.
Matched MeSH terms: Asian Continental Ancestry Group/genetics*
This study aimed to establish a safety zone for the placement of mini-implants in the buccal surface between the second maxillary premolar (PM2) and first maxillary molar (M1) of Mongoloids.
Matched MeSH terms: Asian Continental Ancestry Group*
OBJECTIVE: Asians are known to have different tear characteristics compared to Caucasians that may affect contact lens wear. There are scanty research studies that have evaluated tears during continuous wear contact lens in Asia. The present study aims to evaluate changes in tears in subjects wearing continuous wear rigid gas permeable contact lens (CWRGP) for 6 months.
MATERIALS AND METHODS: Thirty five neophyte subjects (21 females, 14 females) were recruited for this study. Subjects were fitted with CWRGP lenses with Dk of 163 on both eyes. Tear was evaluated using Phenol red thread test (PRT), tear break up time (TBUT) test and tear meniscus height (TMH) measurement. Non parametric and parametric analyses were used to compare the parameters.
RESULTS: Values at baseline (BL) and six months (6M) were as follow: PRT, BL=19.10 ± 3.86 mm, 6M= 21.02 ± 4.27 mm, TBUT, BL= 8.58 ± 4.90 sec, 6M=8.08 ± 5.32 sec, TMH, BL= 0.38 ± 0.12 mm, 6M= 0.34 ± 0.07 mm. Statistical analysis showed significant difference in tear volume for PRT only at 6 months (p=0.007).
CONCLUSION: Our analysis showed minimal change in the tear characteristics after six months of CWRGP lens wear, which indicated low impact of CWRGP contact lens on tears characteristics of Asian eyes. However, careful monitoring is required to prevent development of adverse events during contact lens wear.
Matched MeSH terms: Asian Continental Ancestry Group*
In Duchenne muscular dystrophy (DMD), identification of one nonsense mutation in the DMD gene has been considered an endpoint of genetic diagnosis. Here, we identified two closely spaced nonsense mutations in the DMD gene. In a Malaysian DMD patient two nonsense mutations (p.234S>X and p.249Q>X, respectively) were identified within exon 8. The proband's mother carried both mutations on one allele. Multiple mutations may explain the occasional discrepancies between genotype and phenotype in dystrophinopathy.
Matched MeSH terms: Asian Continental Ancestry Group/genetics
Recently, molecular testing for GJB2 mutations has become the standard of care for the diagnosis of patients with non syndromic hearing impairment of unknown cause. The aims of this study are to determine the association between GJB2 mutation and GJB6 and to report the variation of mutations in deaf students who have heterozygous GJB2. This retrospective study was conducted at Universiti Kebangsaan Malaysia Medical Center (UKMMC). Data was collected from previous files and records from Tissue Engineering and Human Genetic Research Group Laboratory. Approval from Ethical Committee was obtained prior to the study. A total of 138 students have been screened in previous studies in UKMMC for the presence of GJB2 mutations as a cause for hearing loss. Thirty four of the 138 subjects have GJB2 mutations; 2 showed homozygous mutations whereas another 32 were heterozygous for GJB2 gene mutation. Only 31 DNA samples of students presented with sensorineural hearing loss with heterozygous mutation in GJB2 gene were included in this study. The sequencing results obtained were analyzed. The degree of hearing loss of those students with association between GJB2 mutation and GJB6 mutation will be discussed. Five out of 31 subjects (16.2%) have mutations in their GJB6 gene, suggesting a digenic inheritance of GJB2/GJB6 mutation. In total, four novel mutations were identified; E137D (n=1), R32Q (n=1), E101K (n=1) and Y156H (n=1) and one mutation deletion; 366delT (n=1). All students with association GJB2 mutation and GJB6 showed severe to profound hearing loss in both ears. Interestingly this study not detected the large deletion of 342 kb in GJB6 gene suggesting that the mutation is very rare in this region compared to certain parts of the world.
Matched MeSH terms: Asian Continental Ancestry Group/genetics*
The HUGO Pan-Asian SNP consortium conducted the largest survey to date of human genetic diversity among Asians by sampling 1,719 unrelated individuals among 71 populations from China, India, Indonesia, Japan, Malaysia, the Philippines, Singapore, South Korea, Taiwan, and Thailand. We have constructed a database (PanSNPdb), which contains these data and various new analyses of them. PanSNPdb is a research resource in the analysis of the population structure of Asian peoples, including linkage disequilibrium patterns, haplotype distributions, and copy number variations. Furthermore, PanSNPdb provides an interactive comparison with other SNP and CNV databases, including HapMap3, JSNP, dbSNP and DGV and thus provides a comprehensive resource of human genetic diversity. The information is accessible via a widely accepted graphical interface used in many genetic variation databases. Unrestricted access to PanSNPdb and any associated files is available at: http://www4a.biotec.or.th/PASNP.
Matched MeSH terms: Asian Continental Ancestry Group/genetics*
East Asian and white Western observers employ different eye movement strategies for a variety of visual processing tasks, including face processing. Recent eye tracking studies on face recognition found that East Asians tend to integrate information holistically by focusing on the nose while white Westerners perceive faces featurally by moving between the eyes and mouth. The current study examines the eye movement strategy that Malaysian Chinese participants employ when recognizing East Asian, white Western, and African faces. Rather than adopting the Eastern or Western fixation pattern, Malaysian Chinese participants use a mixed strategy by focusing on the eyes and nose more than the mouth. The combination of Eastern and Western strategies proved advantageous in participants' ability to recognize East Asian and white Western faces, suggesting that individuals learn to use fixation patterns that are optimized for recognizing the faces with which they are more familiar.
Matched MeSH terms: Asian Continental Ancestry Group*
There have been numerous studies linking complement components and the pathogenesis of systemic lupus erythematosus (SLE). This is due to their numerous roles in modulating immune responses in the human body. This study examined the association of C2 and C7 genetic polymorphisms with the susceptibility to SLE based on two separate cohorts of patient and control samples from Malaysia. The 28-bp deletion in the C2 exon-intron junction and single nucleotide polymorphism in the 3'untranslated region in the C7 genes were detected based on direct polymerase chain reaction (PCR) and PCR-restriction fragment length polymorphism, respectively. A total of 150 patient and 150 healthy control samples were screened, but there was no association detected between either genes. All individuals presented with null deletion in C2 genes, while the C allele and CC genotypes were most commonly scored. These overall results suggest a lack of strong association with the C2 and C7 gene polymorphisms to the susceptibility of SLE in the Malaysian population.
Matched MeSH terms: Asian Continental Ancestry Group/genetics
Humans reached present-day Island Southeast Asia (ISEA) in one of the first major human migrations out of Africa. Population movements in the millennia following this initial settlement are thought to have greatly influenced the genetic makeup of current inhabitants, yet the extent attributed to different events is not clear. Recent studies suggest that south-to-north gene flow largely influenced present-day patterns of genetic variation in Southeast Asian populations and that late Pleistocene and early Holocene migrations from Southeast Asia are responsible for a substantial proportion of ISEA ancestry. Archaeological and linguistic evidence suggests that the ancestors of present-day inhabitants came mainly from north-to-south migrations from Taiwan and throughout ISEA approximately 4,000 years ago. We report a large-scale genetic analysis of human variation in the Iban population from the Malaysian state of Sarawak in northwestern Borneo, located in the center of ISEA. Genome-wide single-nucleotide polymorphism (SNP) markers analyzed here suggest that the Iban exhibit greatest genetic similarity to Indonesian and mainland Southeast Asian populations. The most common non-recombining Y (NRY) and mitochondrial (mt) DNA haplogroups present in the Iban are associated with populations of Southeast Asia. We conclude that migrations from Southeast Asia made a large contribution to Iban ancestry, although evidence of potential gene flow from Taiwan is also seen in uniparentally inherited marker data.
Matched MeSH terms: Asian Continental Ancestry Group/genetics
PURPOSE: To determine the distribution of higher-order corneal and ocular aberrations in a healthy refractive surgery population.
SETTING: Island Hospital, Penang, Malaysia.
METHODS: In this prospective observational study, 1 eye of ethnic Chinese refractive surgery patients was evaluated with an Orbscan II corneal topographer and a Zywave Hartmann-Shack aberrometer with a 6.0 mm pupil. Height data were analyzed to derive the higher-order aberrations (HOAs) from the 3rd to 5th Zernike order.
RESULTS: The mean spherical equivalent in the 70 eyes evaluated was -6.46 diopters +/- 3.10 (SD). The mean total corneal HOA was 0.574 +/- 0.218 microm (range 0.269 to 1.249 microm) and the mean total ocular HOA, 0.525 +/- 0.354 microm (range 0.138 to 2.145 microm). There was no statistically significant correlation with age. The mean 3rd-order ocular aberration was 0.399 +/- 0.287 microm; the mean 4th-order, 0.297 +/- 0.223 microm; and the mean 5th-order, 0.108 +/- 0.101 microm. Corneal spherical aberration was greater than ocular spherical aberration (mean 0.312 +/- 0.114 microm versus 0.200 +/- 0.170 microm). Multilinear regression showed that the only dependent that predicted ocular spherical aberration was anterior corneal asphericity (r(2) = 0.227, F = 17.95, PAsian Chinese eyes were significantly greater than that reported in other populations. Population differences in wavefront errors were significant, and this should be noted in patient management.
Matched MeSH terms: Asian Continental Ancestry Group/ethnology*
The aim of the present study was to compare, in a case-control study, the prevalence of nucleotide 211 guanine to adenine (G-->A) mutation of uridine diphosphoglucuronosyl transferase (UGT1A1) gene in Malaysian Chinese newborns with and without severe hyperbilirubinemia (total serum bilirubin >250 micromol/L during first 48 h of life or > or =300 micromol/L thereafter), and to determine whether this mutation was a significant risk factor associated with severe hyperbilirubinemia.
Matched MeSH terms: Asian Continental Ancestry Group/genetics
The influence of an individuals' belief in their ability to resist drinking alcohol has recognised importance in understanding the pattern of drinking behaviours among Caucasian samples. Measures used to investigate this construct, such as the drinking refusal self-efficacy questionnaire-revised (DRSEQ-R; [Oei, T. P. S., Hasking, P. A., & Young, R. M. (2005). Drinking refusal self-efficacy questionnaire-revised (DRSEQ-R): A new factor structure with confirmatory factor analysis. Drug and Alcohol Dependence, 78, 297-307.]) have been widely used and have established psychometric properties. However, the exploration of the utility of this questionnaire with samples of different ethnicity, religion and living in different countries remains scarce. In the current study, Arab Muslim samples living in the United Arab Emirates and Oman (n=356) and Asian predominately Muslim samples living in Malaysia and Indonesia (n=256) were used. Exploratory and confirmatory factor analysis demonstrated that the DRSEQ-R has a three factor structure. Internal consistency ranged from alpha .96 to alpha .86 and validity was good. This study offers evidence of the utility of this measure with Arab and Asian samples.
Matched MeSH terms: Asian Continental Ancestry Group/psychology*