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Fulltext Association of Glaucoma Risk Genes with Retinal Nerve Fiber Layer in a Multi-ethnic Asian Population: The Singapore Epidemiology of Eye Diseases Study

Chai X, Low KY, Tham YC, Chee ML, Thakur S, Zhang L, et al.

Invest Ophthalmol Vis Sci, 2020 08 03;61(10):37.
PMID: 32821913 DOI: 10.1167/iovs.61.10.37

Purpose: Genome-wide association studies have identified several genes associated with glaucoma. However, their roles in the pathogenesis of glaucoma remain unclear, particularly their effects on retinal nerve fiber layer (RNFL) thickness. The aim of this study was to investigate the associations between the identified glaucoma risk genes and RNFL thickness.
Methods: A total of 3843 participants (7,020 healthy eyes) were enrolled from the Singapore Epidemiology of Eye Diseases (SEED) study, a population-based study composing of three major ethnic groups-Malay, Indian, and Chinese-in Singapore. Ocular examinations were performed, and spectral-domain optical coherence tomography (SD-OCT) was used to measure circumpapillary RNFL thickness. We selected 35 independent glaucoma-associated genetic loci for analysis. An linear regression model was conducted to determine the association of these variants with circumpapillary RNFL, assuming an additive genetic model. We conducted association analysis in each of the three ethnic groups, followed by a meta-analysis of them.
Results: The mean age of the included participants was 59.4 ± 8.9 years, and the mean RFNL thickesss is 92.3 ± 11.2 µm. In the meta-analyses, of the 35 glacuoma loci, we found that only SIX6 was significantly associated with reduction in global RNFL thickness (rs33912345; β = -1.116 um per risk allele, P = 1.64E-05), and the effect size was larger in the inferior RNFL quadrant (β = -2.015 µm, P = 2.9E-6), and superior RNFL quadrant (β = -1.646 µm, P = 6.54E-5). The SIX6 association were consistently observed across all three ethnic groups. Other than RNFL, we also found several genetic varaints associated with vertical cuo-to-disc ratio (ATOH7, CDKN2B-AS1, and TGFBR3-CDC7), rim area (SIX6 and CDKN2B-AS1), and disc area (SIX6, ATOH7, and TGFBR3-CDC7). The association of SIX6 rs33912345 with NRFL thickness remained similar after further adjusting for disc area and 3 other disc parameter associated SNPs (ATOH7, CDKN2B-AS1, and TGFBR3-CDC7).
Conclusions: Of the 35 glaucoma identified risk loci, only SIX6 is significantly and independently associated with thinner RNFL. Our study further supports the involvement of SIX6 with RNFL thickness and pathogensis of glaucoma.

Matched MeSH terms: Polymorphism, Single Nucleotide/genetics
Fulltext Association of Stress, Mental Health, and VEGFR-2 Gene Polymorphisms with Cardiometabolic Risk in Chinese Malaysian Adults

Yap RWK, Lin MH, Shidoji Y, Yap WS

Nutrients, 2019 May 22;11(5).
PMID: 31121870 DOI: 10.3390/nu11051140

Gene-environment (G × E) interactions involving job stress and mental health on risk factors of cardiovascular disease (CVD) are minimally explored. This study examined the association and G × E interaction effects of vascular endothelial growth factor receptor-2 (VEGFR-2) gene polymorphisms (rs1870377, rs2071559) on cardiometabolic risk in Chinese Malaysian adults. Questionnaires: Job Stress Scale (JSS); Depression, Anxiety, and Stress Scale (DASS-21); and Rhode Island Stress and Coping Inventory (RISCI) were used to measure job stress, mental health, and coping with perceived stress. Cardiometabolic risk parameters were evaluated in plasma and genotyping analysis was performed by real-time polymerase chain reaction. The subjects were 127 Chinese Malaysian adults. The allele frequencies for rs1870377 (A allele and T allele) and rs2071557 (A allele and T allele) polymorphisms were 0.48 and 0.52, and 0.37 and 0.63, respectively. Significant correlations include scores from JSS dimensions with blood glucose (BG) (p = 0.025-0.045), DASS-21 dimensions with blood pressure, BMI, and uric acid (p = 0.029-0.047), and RISCI with blood pressure and BG (p = 0.016-0.049). Significant G × E interactions were obtained for: rs1870377 with stress on total cholesterol (p = 0.035), low density lipoprotein cholesterol (p = 0.019), and apolipoprotein B100 (p = 0.004); and rs2071559 with anxiety on blood pressure (p = 0.006-0.045). The significant G × E interactions prompt actions for managing stress and anxiety for the prevention of CVD.

Matched MeSH terms: Polymorphism, Single Nucleotide/genetics*
Fulltext Association of beta 2 adrenoceptor gene polymorphisms in Malaysian hypertensive subjects

Komara M, Vasudevan R, Ismail P, Bakar SA, Pishva SR, Heidari F

Genet. Mol. Res., 2014;13(2):2939-48.
PMID: 24782128 DOI: 10.4238/2014.April.16.2

The sympathetic nervous system plays a major role in blood pressure regulation. Beta 2 (β2) adrenoceptor gene polymorphisms have been associated with hypertension in different populations with conflicting results. We examined the association of three common polymorphisms, Arg16Gly, Gln27Glu, and Thr164Ile, of the β2 adrenoceptor gene in Malaysian hypertensive subjects. A total of 160 hypertensive and control subjects were recruited. Systolic blood pressure (SBP), diastolic blood pressure (DBP), and anthropometric measurements were obtained from each subject. Biochemical analyses of lipid profiles were conducted with an autoanalyzer. DNA samples were extracted from blood and buccal cells. Genotyping was accomplished with polymerase chain reaction-restriction fragment length polymorphism. SBP, DBP, body mass index, and biochemical factors all differed significantly between case and control subjects (P < 0.05). The genotype frequencies of Arg16Arg, Arg16Gly, and Gly16Gly were 22.5, 70, and 7.5% among cases and 33.1, 63.1, and 3.8% among controls, respectively. The genotype frequencies of Gln27Gln, Gln27Glu, and Glu27Glu among cases were 41.1, 50, and 1.9% compared to 77.5, 20.6, and 1.9% among controls, respectively. In this study, the Gln27Glu polymorphism was significantly associated with Malaysian hypertensive subjects (P < 0.05). Therefore, the Gln27Glu polymorphism of the β2 adrenoceptor could be a risk factor associated with hypertension among Malaysians.

Matched MeSH terms: Polymorphism, Single Nucleotide/genetics
Association of deleted in liver cancer-1 gene polymorphism with increased risk of chronicity of disease among Malaysian patients with hepatitis B infection

Riazalhosseini B, Mohamed R, Devi Apalasamy Y, Mohamed Z

Pharmacogenet Genomics, 2021 Dec 01;31(9):185-190.
PMID: 34320605 DOI: 10.1097/FPC.0000000000000439

OBJECTIVE: The aim of this study is to examine the association between genetic variations in deleted in liver cancer 1 (DLC1) gene with progression of the hepatitis B virus (HBV) infection.
METHODS: A total of 623 subjects were included in this study, of whom, 423 were chronic hepatitis B (CHB) patients without liver cirrhosis or hepatocellular carcinoma (HCC), 103 CHB with either liver cirrhosis ± HCC and 97 individuals who had resolved HBV. Two single-nucleotide polymorphisms rs3739298 and rs532841 of DLC1 gene were genotyped using the Sequenom MassARRAY platform.
RESULTS: Our results indicated significant differences between the chronic HBV and resolved HBV groups in genotype and allele frequencies of DLC1-rs3739298 [odds ratio (OR) = 2.23; 95% confidence interval (CI): 1.24-3.99; P = 0.007] and (OR = 1.54; 95% CI: 1.07-2.22; P = 0.021), respectively. Moreover, haplotype analysis revealed significant associations between chronicity of HBV with TG and GA haplotypes (P = 0.041 and P = 0.042), respectively.
CONCLUSION: A significant association exists between the rs3739298 variant and susceptibility to CHB infection.

Matched MeSH terms: Polymorphism, Single Nucleotide/genetics
Association of functional polymorphisms in 3'-untranslated regions of COMT, DISC1, and DTNBP1 with schizophrenia: a meta-analysis

Mohamed ZI, Tee SF, Tang PY

Psychiatr Genet, 2018 12;28(6):110-119.
PMID: 30252773 DOI: 10.1097/YPG.0000000000000210

INTRODUCTION: In recent years, various studies have accumulated evidence of the involvement of single nucleotide polymorphisms (SNPs) in introns and exons in schizophrenia. The association of functional SNPs in the 3'-untranslated regions with schizophrenia has been explored in a number of studies, but the results are inconclusive because of limited meta-analyses. To systematically analyze the association between SNPs in 3'-untranslated regions and schizophrenia, we conducted a meta-analysis by combining all available studies on schizophrenia candidate genes.
MATERIALS AND METHODS: We searched candidate genes from the schizophrenia database and performed a comprehensive meta-analysis using all the available data up to August 2017. The association between susceptible SNPs and schizophrenia was assessed by the pooled odds ratio with 95% confidence interval using fixed-effect and random-effect models.
RESULTS: A total of 21 studies including 8291 cases and 9638 controls were used for meta-analysis. Three investigated SNPs were rs165599, rs3737597, and rs1047631 of COMT, DISC1, and DTNBP1, respectively. Our results suggested that rs3737597 showed a significant association with schizophrenia in Europeans (odds ratio: 1.584, P: 0.002, 95% confidence interval: 1.176-2.134) under a random-effect framework.
CONCLUSION: This meta-analysis indicated that rs3737597 of DISC1 was significantly associated with schizophrenia in Europeans, and it can be suggested as an ethnic-specific risk genetic factor.

Matched MeSH terms: Polymorphism, Single Nucleotide/genetics
Association study of MCCC1/LAMP3 and DGKQ variants with Parkinson's disease in patients of Malay ancestry

Lim JL, Ng EY, Lim SY, Tan AH, Abdul-Aziz Z, Ibrahim KA, et al.

Neurol Sci, 2021 Oct;42(10):4203-4207.
PMID: 33559030 DOI: 10.1007/s10072-021-05056-x

BACKGROUND: Genome-wide association studies (GWAS) have shown that variants in the 3-methylcrotonyl-CoA carboxylase (MCCC1)/lysosome-associated membrane protein 3 (LAMP3) loci (rs10513789, rs12637471, rs12493050) reduce the risk of Parkinson's disease (PD) in Caucasians, Chinese and Ashkenazi-Jews while the rs11248060 variant in the diacylglycerol kinase theta (DGKQ) gene increases the risk of PD in Caucasian and Han Chinese cohorts. However, their roles in Malays are unknown. Therefore, this study aims to investigate the association of these variants with the risk of PD in individuals of Malay ancestry.
METHODS: A total of 1114 subjects comprising of 536 PD patients and 578 healthy controls of Malay ancestry were recruited and genotyped using Taqman® allelic discrimination assays.
RESULTS: The G allele of rs10513789 (OR = 0.83, p = 0.001) and A allele of rs12637471 (OR = 0.79, p = 0.007) in the MCCC1/LAMP3 locus were associated with a protective effect against developing PD in the Malay population. A recessive model of penetrance showed a protective effect of the GG genotype for rs10513789 and the AA genotype for rs12637471. No association with PD was found with the other MCCC1/LAMP3 rs12493050 variant or with the DGKQ (rs11248060) variant. No significant associations were found between the four variants with the age at PD diagnosis.
CONCLUSION: MCCC1/LAMP3 variants rs10513789 and rs12637471 protect against PD in the Malay population.

Matched MeSH terms: Polymorphism, Single Nucleotide/genetics
Fulltext Bitter receptor gene (TAS2R38) P49A genotypes and their associations with aversion to vegetables and sweet/fat foods in Malaysian subjects

Ooi SX, Lee PL, Law HY, Say YH

Asia Pac J Clin Nutr, 2010;19(4):491-8.
PMID: 21147709

Recently, the bitter receptor gene (TAS2R38) was identified to be responsible for phenylthiocarbamide (PTC) bitter sensitivity. Its two predominant haplotypes at three Single Nucleotide Polymorphisms (SNPs) are found to be definitive for the PTC status, which the ProAlaVal and AlaValIle haplotypes are associated with tasters and non-tasters, respectively. TAS2R38 haplotypes have been reported to influence food preferences (like cruciferous vegetables and fat foods) and cardiovascular disease risk factors. We examined, in 215 Malaysian subjects (100 males, 115 females), the association of the P49A SNP of TAS2R38 with anthropometric measurements and aversion to a list of 36 vegetables, 4 soy products, green tea and 37 sweet/fat foods. The subjects were successfully genotyped as 110 PA, 81 PP and 24 AA (with the A49 allelic frequency of 0.37), by Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP). Ethnicity (Malay, Chinese or Indian), but not gender, was associated with the P49A TAS2R38 genotypes (p<0.001). However, no significant differences in terms of Body Mass Index, Total Body Fat, waist circumference and Waist-Hip Ratio were found between the genotypes (p<0.05). Only aversions to green tea, mayonnaise and whipped cream, but not soy products, vegetables, and other sweet/fat foods, were associated with the P49A genotypes (p<0.05). Therefore, the P49A SNP of the bitter receptor gene TAS2R38 could not serve as a predictor of anthropometric measurements and aversion to vegetables or sweet/fat foods in the sampled Malaysian subjects, and this suggests the existence of other possible factors influencing food selection among Malaysians.

Matched MeSH terms: Polymorphism, Single Nucleotide/genetics
COMT haplotype analyses in Malaysians with schizophrenia

Tee SF, Tang PY, Loh HC

Psychiatry Res, 2012 Jan 30;195(1-2):83-4.
PMID: 21872942 DOI: 10.1016/j.psychres.2011.07.039

The present study included a total 261 patients with schizophrenia and 261 healthy controls to replicate the genetic association between the cathechol-o-methyltransferase gene and schizophrenia using a haplotype block-based gene-tagging. The G-G-G haplotype was found to show a highly significant association with schizophrenia.

Matched MeSH terms: Polymorphism, Single Nucleotide/genetics*
Clinical Relevance of MTHFR, eNOS, ACE, and ApoE Gene Polymorphisms and Serum Vitamin Profile among Malay Patients with Ischemic Stroke

Wei LK, Au A, Menon S, Gan SH, Griffiths LR

J Stroke Cerebrovasc Dis, 2015 Sep;24(9):2017-25.
PMID: 26187788 DOI: 10.1016/j.jstrokecerebrovasdis.2015.04.011

The purpose of this study was threefold. First, it was to determine the relationship between serum vitamin profiles and ischemic stroke. The second purpose was to investigate the association of methylenetetrahydrofolate reductase (MTHFR), endothelial nitric oxide synthase (eNOS), angiotensin converting enzyme (ACE), and apolipoprotein-E (ApoE) gene polymorphisms with ischemic stroke and further correlate with serum vitamin profiles among ischemic stroke patients. The third purpose of the study was to highlight the interaction of MTHFR and eNOS haplotypes with serum vitamin profiles and ischemic stroke risks.

Matched MeSH terms: Polymorphism, Single Nucleotide/genetics*
Comprehensive evaluation of the neuropeptide-Y gene variants in the risk of obesity: a case-control study and meta-analysis

Zain SM, Mohamed Z, Jalaludin MY, Fauzi F, Hamidi A, Zaharan NL

Pharmacogenet Genomics, 2015 Oct;25(10):501-10.
PMID: 26240981 DOI: 10.1097/FPC.0000000000000164

Orexigenic actions mediated by neuropeptide-Y (NPY) promote body weight regulation. Genetic variations in the NPY gene could therefore influence susceptibility to obesity, but results have been conflicting. We have carried out, for the first time, a case-control study to examine the effect of NPY rs16147 and rs5574 variants with the risk of obesity in Asians and also a meta-analysis to summarize the effect of these variants including that of the widely studied rs16139.

Matched MeSH terms: Polymorphism, Single Nucleotide/genetics*
Computational algorithmic and molecular dynamics study of functional and structural impacts of non-synonymous single nucleotide polymorphisms in human DHFR gene

Alam MS, Saleh MA, Mozibullah M, Riham AT, Solayman M, Gan SH

Comput Biol Chem, 2021 Dec;95:107587.
PMID: 34710812 DOI: 10.1016/j.compbiolchem.2021.107587

Human dihydrofolate reductase (DHFR) is a conserved enzyme that is central to folate metabolism and is widely targeted in pathogenic diseases as well as cancers. Although studies have reported the fact that genetic mutations in DHFR leads to a rare autosomal recessive inborn error of folate metabolism and drug resistance, there is a lack of an extensive study on how the deleterious non-synonymous SNPs (nsSNPs) disrupt its phenotypic effects. In this study, we aim at discovering the structural and functional consequences of nsSNPs in DHFR by employing a combined computational approach consisting of ten recently developed in silico tools for identification of damaging nsSNPs and molecular dynamics (MD) simulation for getting deeper insights into the magnitudes of damaging effects. Our study revealed the presence of 12 most deleterious nsSNPs affecting the native phenotypic effects, with three (R71T, G118D, Y122D) identified in the co-factor and ligand binding active sites. MD simulations also suggested that these three SNPs particularly Y122D, alter the overall structural flexibility and dynamics of the native DHFR protein which can provide more understandings into the crucial roles of these mutants in influencing the loss of DHFR function.

Matched MeSH terms: Polymorphism, Single Nucleotide/genetics*
Fulltext Confirmation of five novel susceptibility loci for systemic lupus erythematosus (SLE) and integrated network analysis of 82 SLE susceptibility loci

Molineros JE, Yang W, Zhou XJ, Sun C, Okada Y, Zhang H, et al.

Hum Mol Genet, 2017 03 15;26(6):1205-1216.
PMID: 28108556 DOI: 10.1093/hmg/ddx026

We recently identified ten novel SLE susceptibility loci in Asians and uncovered several additional suggestive loci requiring further validation. This study aimed to replicate five of these suggestive loci in a Han Chinese cohort from Hong Kong, followed by meta-analysis (11,656 cases and 23,968 controls) on previously reported Asian and European populations, and to perform bioinformatic analyses on all 82 reported SLE loci to identify shared regulatory signatures. We performed a battery of analyses for these five loci, as well as joint analyses on all 82 SLE loci. All five loci passed genome-wide significance: MYNN (rs10936599, Pmeta = 1.92 × 10-13, OR = 1.14), ATG16L2 (rs11235604, Pmeta = 8.87 × 10 -12, OR = 0.78), CCL22 (rs223881, Pmeta = 5.87 × 10-16, OR = 0.87), ANKS1A (rs2762340, Pmeta = 4.93 × 10-15, OR = 0.87) and RNASEH2C (rs1308020, Pmeta = 2.96 × 10-19, OR = 0.84) and co-located with annotated gene regulatory elements. The novel loci share genetic signatures with other reported SLE loci, including effects on gene expression, transcription factor binding, and epigenetic characteristics. Most (56%) of the correlated (r2 > 0.8) SNPs from the 82 SLE loci were implicated in differential expression (9.81 × 10-198

Matched MeSH terms: Polymorphism, Single Nucleotide/genetics
Contribution of GABRG2 Polymorphisms to Risk of Epilepsy and Febrile Seizure: a Multicenter Cohort Study and Meta-analysis

Haerian BS, Baum L, Kwan P, Cherny SS, Shin JG, Kim SE, et al.

Mol Neurobiol, 2016 10;53(8):5457-67.
PMID: 26452361 DOI: 10.1007/s12035-015-9457-y

Gamma-aminobutyric acid receptor (GABA-A) is the most common receptor of fast synaptic inhibition in the human brain. Gamma protein encoded by the GABRG2 gene is one of the subunits of the GABA-A receptor, which plays an essential role in the function of this receptor. Several studies have identified various febrile seizure (FS) and epilepsy risk variants of GABRG2 gene in different populations, but some others did not support these results. The aim of this case-control study is to investigate whether GABRG2 polymorphisms contribute to susceptibility for FS and epilepsy in pooled data of three cohorts, from Malaysia (composed of Malay, Chinese, and Indian), Hong Kong, and Korea. Furthermore, the pooled dataset of these cohorts with previous reports were meta-analyzed for determining the risk effect size of the rs211037 polymorphism on FS and symptomatic epilepsy (SE). The rs211037, rs210987, rs440218, rs2422106, rs211014, and rs401750 polymorphisms were genotyped in the 6442 subjects (1729 epilepsy and 4713 controls). Results of the case-control study showed associations between rs211037 and the risk of SE in the pooled data from all cohorts (T vs. C, p = 3 × 10(-5), and TT vs. CC, p = 2 × 10(-5)) and the risk of partial seizure in the combined data of Malaysia and Hong Kong (both T vs. C and TT vs. CC, p = 2 × 10(-6)). The rs211037-rs210987 and rs2422106-rs211014-rs401750 haplotypes were also associated with susceptibility to SE in Chinese. Meta-analysis of all Asians identified association between rs211037 and FS and SE (T vs. C, p = 4 × 10(-4), and p = 4 × 10(-3), respectively). In conclusion, rs211037 alone may be a risk factor for FS, partial seizure, and SE, and in linkage disequilibrium with rs210987 can contribute to FS and SE in Asians, particularly in Chinese.

Matched MeSH terms: Polymorphism, Single Nucleotide/genetics*
Contribution of TIMP4 rs3755724 polymorphism to susceptibility to focal epilepsy in Malaysian Chinese

Haerian BS, Sha'ari HM, Fong CY, Tan HJ, Wong SW, Ong LC, et al.

J Neuroimmunol, 2015 Jan 15;278:137-43.
PMID: 25595263 DOI: 10.1016/j.jneuroim.2014.12.016

Neuroinflammation can damage the brain and plays a critical role in the pathophysiology of epilepsy. Tissue inhibitor of metalloproteinase 4 (TIMP4) is an inflammation-induced apoptosis and matrix turnover factor involved in several neuronal disorders and inflammatory diseases. Evidence has shown linkage disequilibrium between rs3755724 (-55C/T) of this gene with synapsin 2 (SYN2) rs3773364 and peroxisome proliferator-activated G receptor (PPARG) rs2920502 loci, which contribute to epilepsy in Caucasians. The aim of this study was to examine the association of these loci alone or their haplotypes with the risk of epilepsy in the Malaysian population. Genomic DNA of 1241 Malaysian Chinese, Indian, and Malay subjects (670 patients with epilepsy and 571 healthy individuals) was genotyped for the candidate loci by using the Sequenom MassArray method. Allele and genotype association of rs3755724 with susceptibility to epilepsy was significant in the Malaysian Chinese with focal epilepsy under codominant and dominant models (C vs. T: 1.5 (1.1-2.0), p=0.02; CT vs. TT: 1.8 (1.2-2.8), p=0.007 and 1.8 (1.2-2.7), p=0.006, respectively). The T allele and the TT genotype were more common in patients than in controls. No significant association was found between rs2920502 and rs3773364-rs3755724-rs2920502 haplotypes for susceptibility to epilepsy in each ethnicity. This study provides evidence that the promoter TIMP4 rs3755724 is a new focal epilepsy susceptibility variant that is plausibly involved in inflammation-induced seizures in Malaysian Chinese.

Matched MeSH terms: Polymorphism, Single Nucleotide/genetics*
De novo assembly of genome and development of polymorphic microsatellite loci in the blue swimming crab (Portunus pelagicus) using RAD approach

Wu Q, Miao G, Li X, Liu W, Ikhwanuddin M, Ma H

Mol Biol Rep, 2018 Dec;45(6):1913-1918.
PMID: 30203240 DOI: 10.1007/s11033-018-4339-9

The blue swimming crab (Portunus pelagicus) is a valuable marine fishery resource in Indo-West Pacific Ocean. So far, rare genetic resource of this species is available. In this report, the restriction-site associated DNA (RAD) approach was employed to mine the genomic information and identify molecular markers in P. pelagicus. A total of 0.82 Gbp clean data were generated from the genome of individual "X2A". De novo assembly produced 85,796 contigs with an average length of 339 bp. A total of 45,464 putative SNPs and 17,983 microsatellite loci were identified from the genomes of ten individuals. Furthermore, 31 pairs of primers were successfully designed, with 16 of them exhibiting polymorphism in a wild population. For these polymorphic loci, the expected and observed alleles per locus ranged from 1.064 to 7.314 and from 2 to 11, respectively. The expected and observed heterozygosity per locus ranged from 0.0615 to 0.819 and from 0.0626 to 1.000, respectively. Nine loci showed high informative with polymorphism information content (PIC) > 0.5. Five loci significantly deviated from Hardy-Weinberg equilibrium in the samples analyzed. No linkage disequilibrium was found among the 16 polymorphic microsatellite loci. This study provided massive genetic resource and polymorphic molecular markers that should be helpful for studies on conservation genetics, population dynamics and genetic diversity of P. pelagicus and related crab species.

Matched MeSH terms: Polymorphism, Single Nucleotide/genetics
De-novo mutations and genetic variation in the SCN1A gene in Malaysian patients with generalized epilepsy with febrile seizures plus (GEFS+)

Tan EH, Razak SA, Abdullah JM, Mohamed Yusoff AA

Epilepsy Res, 2012 Dec;102(3):210-5.
PMID: 22944210 DOI: 10.1016/j.eplepsyres.2012.08.004

Generalized epilepsy with febrile seizures plus (GEFS+) comprises a group of clinically and genetically heterogeneous epilepsy syndrome. Here, we provide the first report of clinical presentation and mutational analysis of SCN1A gene in 36 Malaysian GEFS+ patients. Mutational analysis of SCN1A gene revealed twenty seven sequence variants (missense mutation and silent polymorphism also intronic polymorphism), as well as 2 novel de-novo mutations were found in our patients at coding regions, c.5197A>G (N1733D) and c.4748A>G (H1583R). Our findings provide potential genetic insights into the pathogenesis of GEFS+ in Malaysian populations concerning the SCN1A gene mutations.

Matched MeSH terms: Polymorphism, Single Nucleotide/genetics
Determinants of low bone mineral density in children with epilepsy

Fong CY, Kong AN, Noordin M, Poh BK, Ong LC, Ng CC

Eur. J. Paediatr. Neurol., 2018 Jan;22(1):155-163.
PMID: 29122496 DOI: 10.1016/j.ejpn.2017.10.007

INTRODUCTION: Children with epilepsy on long-term antiepileptic drugs (AEDs) are at risk of low bone mineral density (BMD). The aims of our study were to evaluate the prevalence and determinants of low BMD among Malaysian children with epilepsy.
METHOD: Cross-sectional study of ambulant children with epilepsy on long-term AEDs for >1 year seen in a tertiary hospital in Malaysia from 2014 to 2015. Detailed assessment of anthropometric measurements; environmental lifestyle risk factors; serum vitamin D, calcium and parathyroid hormone levels; genotyping of single nucleotide polymorphisms of genes in vitamin D and calcium metabolism; and lumbar spine BMD were obtained. Low BMD was defined as BMD Z-score ≤ -2.0 SD.
RESULTS: Eighty-seven children with mean age of 11.9 years (56 males) participated in the study. The prevalence of low lumbar BMD was 21.8% (19 patients). Multivariate logistic regression analysis identified polytherapy >2 AEDs (OR: 7.86; 95% CI 1.03-59.96), small frame size with wrist breadth of <15th centile (OR 14.73; 95% CI 2.21-98.40), and body mass index Z-score 2 AEDs, underweight or with small frame size as they are at higher risk of having low BMD.

Matched MeSH terms: Polymorphism, Single Nucleotide/genetics
Fulltext Development and Validation of a High-Density SNP Genotyping Array for African Oil Palm

Kwong QB, Teh CK, Ong AL, Heng HY, Lee HL, Mohamed M, et al.

Mol Plant, 2016 Aug 01;9(8):1132-1141.
PMID: 27112659 DOI: 10.1016/j.molp.2016.04.010

High-density single nucleotide polymorphism (SNP) genotyping arrays are powerful tools that can measure the level of genetic polymorphism within a population. To develop a whole-genome SNP array for oil palms, SNP discovery was performed using deep resequencing of eight libraries derived from 132 Elaeis guineensis and Elaeis oleifera palms belonging to 59 origins, resulting in the discovery of >3 million putative SNPs. After SNP filtering, the Illumina OP200K custom array was built with 170 860 successful probes. Phenetic clustering analysis revealed that the array could distinguish between palms of different origins in a way consistent with pedigree records. Genome-wide linkage disequilibrium declined more slowly for the commercial populations (ranging from 120 kb at r(2) = 0.43 to 146 kb at r(2) = 0.50) when compared with the semi-wild populations (19.5 kb at r(2) = 0.22). Genetic fixation mapping comparing the semi-wild and commercial population identified 321 selective sweeps. A genome-wide association study (GWAS) detected a significant peak on chromosome 2 associated with the polygenic component of the shell thickness trait (based on the trait shell-to-fruit; S/F %) in tenera palms. Testing of a genomic selection model on the same trait resulted in good prediction accuracy (r = 0.65) with 42% of the S/F % variation explained. The first high-density SNP genotyping array for oil palm has been developed and shown to be robust for use in genetic studies and with potential for developing early trait prediction to shorten the oil palm breeding cycle.

Matched MeSH terms: Polymorphism, Single Nucleotide/genetics*
Fulltext Development of high-throughput SNP-based genotyping in Acacia auriculiformis x A. mangium hybrids using short-read transcriptome data

Wong MM, Cannon CH, Wickneswari R

BMC Genomics, 2012;13:726.
PMID: 23265623 DOI: 10.1186/1471-2164-13-726

Next Generation Sequencing has provided comprehensive, affordable and high-throughput DNA sequences for Single Nucleotide Polymorphism (SNP) discovery in Acacia auriculiformis and Acacia mangium. Like other non-model species, SNP detection and genotyping in Acacia are challenging due to lack of genome sequences. The main objective of this study is to develop the first high-throughput SNP genotyping assay for linkage map construction of A. auriculiformis x A. mangium hybrids.

Matched MeSH terms: Polymorphism, Single Nucleotide/genetics*
Dietary fat interacts with the -514C>T polymorphism in the hepatic lipase gene promoter on plasma lipid profiles in a multiethnic Asian population: the 1998 Singapore National Health Survey

Tai ES, Corella D, Deurenberg-Yap M, Cutter J, Chew SK, Tan CE, et al.

J Nutr, 2003 Nov;133(11):3399-408.
PMID: 14608050 DOI: 10.1093/jn/133.11.3399

We have previously reported an interaction between -514C>T polymorphism at the hepatic lipase (HL) gene and dietary fat on high-density lipoprotein-cholesterol (HDL-C) metabolism in a representative sample of white subjects participating in the Framingham Heart Study. Replication of these findings in other populations will provide proof for the relevance and consistency of this marker as a tool for risk assessment and more personalized cardiovascular disease prevention. Therefore, we examined this gene-nutrient interaction in a representative sample of Singaporeans (1324 Chinese, 471 Malays and 375 Asian Indians) whose dietary fat intake was recorded by a validated questionnaire. When no stratification by fat intake was considered, the T allele was associated with higher plasma HDL-C concentrations (P = 0.001), higher triglyceride (TG) concentrations (P = 0.001) and higher HDL-C/TG ratios (P = 0.041). We found a highly significant interaction (P = 0.001) between polymorphism and fat intake in determining TG concentration and the HDL-C/TG ratio (P = 0.001) in the overall sample even after adjustment for potential confounders. Thus, TT subjects showed higher TG concentrations only when fat intake supplied >30% of total energy. This interaction was also found when fat intake was considered as continuous (P = 0.035). Moreover, in the upper tertile of fat intake, TT subjects had 45% more TG than CC individuals (P < 0.01). For HDL-C concentration, the gene-diet interaction was significant (P = 0.015) only in subjects of Indian origin. In conclusion, our results indicate that there are differences in the association of -514C>T polymorphism with plasma lipids according to dietary intake and ethnic background. Specifically, the TT genotype is associated with a more atherogenic lipid profile when subjects consume diets with a fat content > 30%.

Matched MeSH terms: Polymorphism, Single Nucleotide/genetics*

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