Association between Genetic Polymorphism of SCN1A, GABRA1 and ABCB1 and Drug Responsiveness in Vietnamese Epileptic Children.

Background and Objectives: Drug resistant epilepsy (DRE) is a major hurdle in epilepsy, which hinders clinical care, patients' management and treatment outcomes. DRE may partially result from genetic variants that alter proteins responsible for drug targets and drug transporters in the brain. We aimed to examine the relationship between SCN1A, GABRA1 and ABCB1 polymorphism and drug response in epilepsy children in Vietnam. Materials and Methods: In total, 213 children diagnosed with epilepsy were recruited in this study (101 were drug responsive and 112 were drug resistant). Sanger sequencing had been performed in order to detect six single nucleotide polymorphisms (SNPs) belonging to SCN1A (rs2298771, rs3812718, rs10188577), GABRA1 (rs2279020) and ABCB1 (rs1128503, rs1045642) in study group. The link between SNPs and drug response status was examined by the Chi-squared test or the Fisher's exact test. Results: Among six investigated SNPs, two SNPs showed significant difference between the responsive and the resistant group. Among those, heterozygous genotype of SCN1A rs2298771 (AG) were at higher frequency in the resistant patients compared with responsive patients, playing as risk factor of refractory epilepsy. Conversely, the heterozygous genotype of SCN1A rs3812718 (CT) was significantly lower in the resistant compared with the responsive group. No significant association was found between the remaining four SNPs and drug response. Conclusions: Our study demonstrated a significant association between the SCN1A genetic polymorphism which increased risk of drug-resistant epilepsy in Vietnamese epileptic children. This important finding further supports the underlying molecular mechanisms of SCN1A genetic variants in the pathogenesis of drug-resistant epilepsy in children.

Pain is common in early onset Parkinson's disease and pain severity is associated with age and worsening of motor and non-motor symptoms.

The consequences of pain in early onset Parkinson's disease (EOPD) remain under appreciated even though pain may exert an increasingly negative impact on patient quality of life as motor and non-motor symptoms worsen. In this prospective study, we investigate the prevalence and severity of pain in 135 Vietnamese patients with EOPD from three medical centers using the King's PD Pain Scale (KPPS), the Mini Mental Status Exam (MMSE), the Unified Parkinson's Disease Rating Scale (UPDRS) and the Non-Motor Symptoms Scale (NMSS). Pain was reported by 79.3%. The most common subtype of pain was musculoskeletal (70.1%), followed by nocturnal (43.9%), radicular (43.0%), chronic (42.1%), fluctuation-related (34.6%) and orofacial pain (16.8%). Most patients (74.8%) experienced more than one pain subtype. Fluctuation-related pain and orofacial pain were significantly more prevalent among patients with higher Hoehn & Yahr (H&Y) stages (3-5) versus lower H&Y stages (1-2). Pain subtype and severity were not significantly related to gender or age of PD onset. Patients with H&Y stages 3-5 had statistically significantly higher KPPS scores for fluctuation-related pain (p = 0.018) and radicular pain (p = 0.026). Independent associations were found between pain severity and age (p = 0.028), depression severity (p = 0.018), perceptual problems/hallucinations (p = 0.033) and sexual function (p = 0.024). Patients with depression and higher H&Y stages (3-5) had statistically significantly higher mean KPPS scores versus patients without depression and at lower H&Y stages (1-2). Pain may be more common and severe in EOPD patients than previously appreciated. Older age, depression, perceptual problems/hallucinations and sexual dysfunction were independently associated with higher pain severity.

Copy number variations of cytochrome P450 genes in Kinh Vietnamese.

Background: The cytochrome P450 (CYP450) family is well known as a major group of drug metabolizing enzymes. The polymorphism of CYP450 genes is the main factor having an impact on the interindividual difference in drug response, including drug efficacy and drug safety. The single nucleotide polymorphism (SNPs) of Vietnamese Kinh has been widely studied, but information about the copy number variations (CNVs) of other CYP450 genes is still unknown. Objective: To identify the CNV variability of CYP450 in 154 healthy unrelated Kinh Vietnamese, except eCYP2D6, which was previously reported. Methods: Multiplex Ligation-Dependent Probe Amplification (MLPA) was applied for determination of copy number of 10 CYP450 genes. Later, PCR or quantitative PCR (qPCR) was used to confirm the detected CNVs in randomly chosen subjects. Results: Of the 154 subjects, along with CYP2D6, 4 other CYP450 genes showed CNVs including duplications (CYP1B1), deletions (CYP2A6 and CYP2C9), and both duplications and deletions (CYP2E1). Among these, CYP2A6 exhibited the greatest frequency of CNVs compared with other CYP450, in which CYP2A6Del accounted for 11%. Meanwhile, allele CYP2E1Del showed the lowest frequency with only 0.3%. Conclusions: The present study provides new insight into CYP450 CNVs in the Kinh Vietnamese cohort. Our data have contributed to genetic profiling of CYP450 CNVs in Vietnam, which would be helpful for facilitating implementation of pharmacogenetics in drug dosing adjustment in Vietnam.

Association of ADH1B rs1229984, ADH1C rs698, and ALDH2 rs671 with Alcohol abuse and Alcoholic Cirrhosis in People Living in Northeast Vietnam.

OBJECTIVE: Alcohol abuse can cause developing cirrhosis, even liver cancer. Several single nucleotide polymorphisms (SNPs) of ADH1B, ADH1C, and ALDH2 genes have been reported to be associated with alcohol abuse and alcoholic cirrhosis (ALC). This study investigated the association between three SNPs of ADH1B rs1229984, ADH1C rs698, and ALDH2 rs671 with alcohol abuse and ALC in people living in the Northeast region of Vietnam. METHODS: 306 male participants were recruited including 206 alcoholics (106 ALC, 100 without ALC) and 100 healthy non-alcoholics. Clinical characteristics were collected by clinicians. Genotypes were identified by Sanger sequencing. Chi-Square (χ2) and Fisher-exact tests were used to assess the differences in age and clinical characteristics, Child-Pugh score, frequencies of alleles and genotypes. RESULT: Our data showed that the frequency of ALDH2*1 was significantly higher in alcoholics (88.59%) and ALC groups (93.40%) than that of healthy non-alcoholics (78.50%) with p=0.0009 and non-ALC group (83.50%) with p=0.002, respectively. We detected opposite results when examined ALDH2*2. Frequency of combined genotypes with high acetaldehyde accumulation were significantly lower in alcoholics and ALC group than those of control groups with p=0.005 and p=0.008, respectively. Meanwhile, the proportion of combined genotypes with non-acetaldehyde accumulation were significantly two times higher in the ALC group (19.98%) than those of the non-ALC group (8%) with p=0.035. These combined genotypes showed a decreasing trend in the Child-Pugh score from likely phenotype causing risk for non-acetaldehyde accumulation to high acetaldehyde accumulation. CONCLUSION: The ALDH2*1 allele was found as a risk factor for alcohol abuse and ALC, and combined genotypes of ADH1B rs1229984, ADH1C rs698, and ALDH2 rs671 with non-acetaldehyde accumulation increase ALC risk. In contrast, ALDH2*2 and the genotype combinations related to high acetaldehyde accumulation were protective factors against alcohol abuse and ALC.

Severe loss of adipose tissue in a Vietnamese lipodystrophy patient caused by LMNA p.G465D mutation: a first clinical characterization and two-year follow-up.

OBJECTIVES: Familial partial lipodystrophy type 2 is the most well-known subtype of lipodystrophy. We describe for the first time the phenotype of a case with lipodystrophy, who carried heterozygous mutation c.G1394A (p.G465D) in the LMNA gene. CASE PRESENTATION: A 17-year-old girl was diagnosed with FPLD2 due to severe loss of subcutaneous fat in the extremities, buttocks and metabolic complications. However, there was no accumulation of fat over her face and neck, which is remarkably different from the FPLD2 clinical phenotypes. Two years of surveillance showed the challenge due to unable control of insulin resistance, glucose and lipid metabolism. Whole exome sequencing revealed the heterozygous mutation c.1394G>A at exon 11 of LMNA gene (p.G465D). CONCLUSIONS: Our case displayed an atypical phenotype of FPLD2 with metabolic anomalies, not cardiovascular diseases. The difficulties of medical management in this case pointed out the urgent need for more effective treatment for individuals suffering from this rare disease.

Novel mutations of the PAX6, FOXC1, and PITX2 genes cause abnormal development of the iris in Vietnamese individuals.

Purpose: Congenital iris abnormality is a feature of several genetic conditions, such as aniridia syndrome and anterior segment degeneration (ASD) disorders. Aniridia syndrome is caused by mutations in the PAX6 gene or its regulatory elements in the locus 11p13 or deletions of contiguous genes, while ASDs are the result of mutations in various genes, such as PAX6, FOXC1, PITX2, and CYP1B1. This study aims to identify pathogenic mutations in Vietnamese individuals with congenital anomalies of the iris. Methods: Genomic DNA was extracted from peripheral blood of 24 patients belonging to 15 unrelated families and their available family members. Multiplex ligation-dependent probe amplification (MLPA) was used to detect the deletions or duplications in the 11p13-14 region, including the PAX6 gene and its neighboring genes. Direct PCR sequencing was used to screen mutations in 13 exons and flanking sequences of the PAX6 gene. The patients without mutation in the PAX6 locus were further analyzed with whole exome sequencing (WES). Identified mutations were tested with segregation analysis in proband family members. Results: We identified a total of 8 novel and 4 recurrent mutations in 20 of 24 affected individuals from 12 families. Among these mutations, one large deletion of the whole PAX6 gene and another deletion of the PAX6 downstream region containing the DCDC1 and ELP4 genes were identified. Eight mutations were detected in PAX6, including four nonsense, three frameshift, and one splice site. In addition, two point mutations were identified in the FOXC1 and PITX2 genes in patients without mutation in PAX6. Some of the mutations segregated in an autosomal dominant pattern where family members were available. Conclusions: This study provides new data on causative mutations in individuals with abnormal development of iris tissue in Vietnam. These results contribute to clinical management and genetic counseling for affected people and their families.

CYP2C19 genetic polymorphism in the Vietnamese population.

Background: Genetic polymorphism of CYP2C19 has been shown to affect enzyme activity and thereby contribute to inter-individual variability in drug metabolism and response. The complete genetic variation of CYP2C19 in Vietnam still remains obscure even though data of common alleles in Vietnamese Kinh have been reported.Aim: To establish the extent of CYP2C19 polymorphism in Vietnamese.Subjects and methods: The promoter and all nine exons of CYP2C19 in 100 healthy unrelated Vietnamese Kinh subjects were sequenced. Additionally, the CYP2C19 variants, *2, *3 and *17 were analysed by RFLP-PCR in 275 subjects of four minor ethnic groups in Vietnam (Tay, Muong, H'Mong and Nung).Results: In 100 Kinh subjects, the percentages of CYP2C19*1, CYP2C19*2, CYP2C19*3 and CYP2C19*17 alleles were 76%, 20.5%, 2.5% and 1%, respectively. Three novel variants in introns 2, 5 and 8 had no impact on mRNA splicing according to the Human Splicing Finder. The prevalence of CYP2C19*17 in Vietnamese Kinh was significantly lower compared with figures found in Western Asia and Europe, while CYP2C19*2 frequency was statistically higher than that in Western Asia and several countries in Europe. The frequency of CYP2C19*2 in Kinh was significantly lower than in the other four ethnic minorities.Conclusion: These results provide information on CYP2C19 polymorphism in the Vietnamese population, which could be useful for optimising drug therapies and precision medicine studies.

Single nucleotide and structural variants of CYP2D6 gene in Kinh Vietnamese population.

CYP2D6 genetic variations could result in alteration of CYP2D6 enzyme activity, leading to dissimilarity among individuals in regard of drug metabolism.This study aims to detect all genetic variants, allele, and genotype frequencies of CYP2D6 gene in 136 unrelated healthy Kinh Vietnamese volunteers. All single nucleotide variants (SNVs) and structural variations (SVs) of CYP2D6 gene were identified by Sanger sequencing and multiplex ligation-dependent probe amplification (MLPA) assay.Totally, 30 SNVs and 9 SVs including a whole gene deletion, 8 hybrid structures, and tandem arrangements were identified. Of the 7 novel SNVs detected, the 3157G>T (R329L) substitution was predicted to be deleterious by PROVEAN; the 3851G>A (W358X) variant resulted in a truncated protein; and the 2988G>A variant located in the intron 6 was predicted to be capable of modifying splicing motif by Human Splicing Finder. We determined 29 different genotypes of CYP2D6 from 136 individuals. The most common alleles were the CYP2D6*10 (43.75%), *1 (18.75%), and tandem arrangement *36-*10 (12.13%).This study provides best information on CYP2D6 polymorphism comprising the newly discovered SNVs, structural variations, and their frequencies in Kinh Vietnamese. These new data would be valuable in view of precise dosing of CYP2D6 metabolized drugs and giving better treatment outcome.

Polymorphic analysis of CYP2C9 gene in Vietnamese population.

Genetic variations in CYP2C9 are associated to inter-individual variability of drugs metabolism and response. The only report has been done previously mainly focusing on the common variant alleles of CYP2C9 in Vietnamese Kinh subjects. However, little is known about the complete spectrum of this gene polymorphism in different ethnic groups of Vietnam. We sequenced the promoter region and all exons of CYP2C9 in 100 healthy unrelated Vietnamese Kinh subjects. Additionally, common CYP2C9 variants, *2 and *3, were also analyzed by RFLP-PCR in extra 194 Kinh subjects and 279 of other four ethnic groups in Vietnam. The results of these common variants observed from five ethnic groups were compared with other populations in the world. Seven previously reported alleles and two genotypes were determined in Kinh subjects. The percentage of CYP2C9*1 and CYP2C9*3 alleles are 96.5 and 3.5%, respectively. We found one novel non-synonymous variant in exon 7 leading to amino acid change at 363 position from proline to histidine. Functional analysis by SIFT and Polyphen-2 indicated that this mutation is intolerant and probably damaging. Prevalence of CYP2C9*2 observed in Vietnamese population was significantly lower compared with that of other populations in the South and West of Asia as well as in Europe. This study provides information of genetic distribution pattern of CYP2C9 in Vietnamese, which would be useful for optimizing drug therapies in Vietnam.

Mutational screening of germline RB1 gene in Vietnamese patients with retinoblastoma reveals three novel mutations.

Purpose: Retinoblastoma (Rb) is a rare and unique eye cancer that usually develops in the retinas of children less than 5 years old due to mutations in the RB1 gene. About 40% of affected individuals have the heritable form making genetics testing of the RB1 gene important for disease management. This study aims to identify germline mutations in RB1 in a cohort of patients with Rb from northern Vietnam. Methods: Genomic DNA was extracted from peripheral blood of 34 patients with Rb (nine unilateral and 25 bilateral cases) and their available parents. Twenty-seven exons, flanking sequences, and the promoter region of RB1 gene were screened for mutations with direct PCR sequencing. Multiplex ligation-dependent probe amplification (MLPA) was applied for patients with negative sequencing results. In the mutation-positive patients, their available parental DNA was analyzed to determine the parental origin of the mutation. Results: Germline mutations in RB1 were identified in 25 (73.53%) of 34 patients (four unilateral and 21 bilateral cases). Of these mutations, 19 were detected, including seven nonsense, six frameshift, four splice-site (one was identified in two siblings), and one missense, with Sanger sequencing. Three novel frameshift mutations were discovered in one unilateral and two bilateral patients. MLPA detected mutations in the RB1 gene in six bilateral cases, of whom five had a whole gene deletion (three familial cases) and one had a partial gene deletion (from exon 4 to exon 27) in one allele of the RB1 gene. Parental testing showed five mutations originated from the fathers and one was inherited from a mother who was mosaic for the mutation. Conclusions: This study provides a data set of germline mutations in the RB1 gene in Vietnamese patients with retinoblastoma. Screening of mutations in the RB1 gene can help to identify heritable Rb and contribute to clinical management and genetic counseling for affected families.

Antimicrobial resistance gene expression associated with multidrug resistant Salmonella spp. isolated from retail meat in Hanoi, Vietnam.

The purpose of this study was to further characterize the multi-antimicrobial resistance and antibiotic resistance gene expression associated with multi-drug resistance (MDR) in Salmonella spp. isolates from retail meats in Hanoi, Vietnam. A total of 14 Salmonella spp. belonging to 9 serotypes (e.g., Warragul, London, Derby, Indiana, Meleagridis, Give, Rissen, Assine, and Typhimurium) were tested for sensitivity to 8 antibiotics. Resistance to at least one antibiotic was shown in 13 strains (92.85%). The multiple antimicrobial resistances accounted for 64.29% of isolates (9/14). One hundred percent of MDR isolates possessed antibiotic resistant genes, in which 17, 16 and 11 genes were found in Salmonella (Salm) Typhimurium S360, S384, S181 respectively; 12 genes in each strain as Indiana, Warragul, and Meleagridis; 11 genes in Give, 8 genes in Derby and 6 genes in Rissen. Three antibiotic resistance genes (ssaQ, aadA, and gyrB) were present in all isolates, whereas Cephalosporin-resistant gene (e.g., CTX-M3-like) was not detected in any isolates. The results suggest that retail meats could constitute a source of human exposure to multi-drug resistant Salmonella and future research should focus on the impact of these MDR source on the human genome. [Int Microbiol 20(2): 85-93 (2017)].

Antimicrobial resistance gene expression associated with multidrug resistant Salmonella spp isolated from retail meat in Hanoi, Vietnam

The purpose of this study was to further characterize the multi-antimicrobial resistance and antibiotic resistance gene expression associated with multi-drug resistance (MDR) in Salmonella spp. isolates from retail meats in Hanoi, Vietnam. A total of 14 Salmonella spp. belonging to 9 serotypes (e.g., Warragul, London, Derby, Indiana, Meleagridis, Give, Rissen, Assine, and Typhimurium) were tested for sensitivity to 8 antibiotics. Resistance to at least one antibiotic was shown in 13 strains (92.85%). The multiple antimicrobial resistances accounted for 64.29% of isolates (9/14). One hundred percent of MDR isolates possessed antibiotic resistant genes, in which 17, 16 and 11 genes were found in Salmonella (Salm) Typhimurium S360, S384, S181 respectively; 12 genes in each strain as Indiana, Warragul, and Meleagridis; 11 genes in Give, 8 genes in Derby and 6 genes in Rissen. Three antibiotic resistance genes (ssaQ, aadA, and gyrB) were present in all isolates, whereas Cephalosporinresistant gene (e.g., CTX-M3-like) was not detected in any isolates. The results suggest that retail meats could constitute a source of human exposure to multi-drug resistant Salmonella and future research should focus on the impact of these MDR source on the human genome (AU)

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Potential effect of combined xenoestrogens during gestation stages on mouse offspring.

The synergistic effect of numerous environmental endocrine disrupting chemicals (EDCs) has raised research concern among researchers. To extend previous studies, the measured additional potential interactions among bisphenol A (BPA), 4-nonylphenol (NP), 4-tert octylphenol (OP) and isobutylparaben (IBP) in mouse model were observed. Pregnant Swiss-albino mice were treated with binary combined chemicals (5, 50 or 500 mg kg(-1) b.wt. day(-1)) from gestation day (GD) 1 to 21. Interestingly, maternal exposure to these EDCs caused fluctuation in GD time, live ratio, female/male ratio, body and organ weights of mouse offspring at postnatal day (PND) 1, 21, and 41 days. At most doses early reduced 0.85 to 1.87 GD compared to controls. Besides females/males ratio showed a significant difference in BPA+ OP, BPA+IBP groups. Female body weight at PND 21 and 41, showed a significant reduction at all combined levels, whereas male offspring showed reduction in weight at dose 50 mg kg(-1) b.wt. day(-1). The potential effects of synergic estrogenicity detected histopathological abnormities, such as ovary analysis revealed increase of corpora lutea, cystic follicles and an endometrial hypertrophy and morphometric changes in uteri measurement. Taken together, these results provided an additional insight into synergistic effects of EDCs toxicology on reproductive tracts.