Genetic variability and haplotype profile of MDR1 in Saudi Arabian males

Multidrug resistant 1 (MDR1) C3435T and G2677T gene polymorphism: impact on the risk of acute rejection in pediatric kidney transplant recipients

BACKGROUND

Tacrolimus is the backbone drug in kidney transplantation. Single nucleotide polymorphism of Multidrug resistant 1 gene can affect tacrolimus metabolism consequently it can affect tacrolimus trough level and incidence of acute rejection. The aim of this study is to investigate the impact of Multidrug resistant 1 gene, C3435T and G2677T Single nucleotide polymorphisms on tacrolimus pharmacokinetics and on the risk of acute rejection in pediatric kidney transplant recipients.

METHODS

Typing of Multidrug resistant 1 gene, C3435T and G2677T gene polymorphism was done using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) for 83 pediatric kidney transplant recipients and 80 matched healthy controls.

RESULTS

In Multidrug resistant 1 gene (C3435T), CC, CT genotypes and C allele were significantly associated with risk of acute rejection when compared to none acute rejection group (P = 0.008, 0.001 and 0.01 respectively). The required tacrolimus doses to achieve trough level were significantly higher among CC than CT than TT genotypes through the 1st 6 months after kidney transplantation. While, in Multidrug resistant 1 gene (G2677T), GT, TT genotypes and T allele were associated with acute rejection when compared to none acute rejection (P = 0.023, 0.033 and 0.028 respectively). The required tacrolimus doses to achieve trough level were significantly higher among TT than GT than GG genotypes through the 1st 6 months after kidney transplantation.

CONCLUSION

The C allele, CC and CT genotypes of Multidrug resistant 1 gene (C3435T) and the T allele, GT and TT genotypes of Multidrug resistant 1 gene (G2677T) gene polymorphism may be risk factors for acute rejection and this can be attributed to their effect on tacrolimus pharmacokinetics. Tacrolimus therapy may be tailored according to the recipient genotype for better outcome.

Genetic Analysis of CYP2C9 with Reference to Drug Response in Epilepsy Patients of Pakistan

Epilepsy is a major global issue. Epilepsy patients are treated with AED (antiepileptic drugs). Interindividual variability in drug response has been documented in several studies. The resistance to drug response may be attributed to genetic polymorphism. The current study was undertaken to investigate the CYP2C9 gene polymorphism associated with antiepileptic drug (AED) resistance in the Pakistani population. The current study included 337 individuals including 100 control subjects, 110 drug-resistant subjects, and 127 drug responders. Genomic DNA was isolated from blood, and amplification of rs1799853 (430C > T) and rs1057910 was carried out by polymerase chain reaction. Genotypes of CYP2C9 SNPs were determined by Sanger’s sequencing. Astounding results were observed in the current study that none of the well-known reported SNPs of CYP2C9 was found in our Pakistani cohorts. However, a novel missense variant (c.374G > A) was found only in drug-resistant patients of the current study. According to the in silico analysis performed by PolyPhen-2, it was observed that this nonsynonymous substitution is likely to be pathogenic. The results of our study demonstrated that rs1799853 and rs1057910 may be involved in drug resistance in the Pakistani population. However, some other variants on CYP2C9 may play a critical role in AED resistance that needs to be explored.

Major CYP450 polymorphism Among Saudi Patients

BACKGROUND

Cytochrome P450 (CYP) contributes to a huge collection of medicinal products' Phase I metabolization. We aimed to summarize and investigate the current evidence regarding the frequency of CYP2D6, CYP2C9, CYP2C19, MDR1 in Saudi Arabia.

METHODS

A computerized search in four databases was done using the relevant keywords. Screening process was done in two steps; title and abstract screening and full-text screening. Data of demographic and characteristics of included studies and patients was extracted and tabulated.

RESULTS

Ten studies were eligible for our criteria and were included in this systematic review. Age of participants ranged between 17-65 years. Only two subjects showed PM phenotype of CYP2C19 in Saudi population. The most frequent alleles were CYP2C19*1 (62.9%), CYP2C19*2 (11.2%-32%), and CYP2C19*17 (25.7%). The CYP2C19m1 was observed in 97 cases of extensive metabolizing (EM) phenotype CYP2C19. Concerning the CYP2C9, the most frequent alleles were CYP2C9*1 and CYP2C9*2, and the most frequent genotype was CYP2C9*1*1. The CYP2D6*41 allele and C1236T MDR1 were the most frequent allele in this population.

CONCLUSION

The current evidence suggests that Saudi Arabians resembled European in the frequency of CYP2C19, Caucasians in both the incidence of CYP2C9 and CYP2C19m1 and absence of CYP2C19m2. The CYP2D6*41 allele frequency in Saudi Arabians is relatively high. We recommend a further research to evaluate the basic and clinical relevance of gene polymorphism in such ethnicity.

Impact of Genetic Polymorphisms on Phenytoin Pharmacokinetics and Clinical Outcomes in the Middle East and North Africa Region

BACKGROUND

Genetic polymorphisms are known to influence outcomes with phenytoin yet effects in the Middle East and North Africa region are poorly understood.

OBJECTIVES

The objective of this systematic review was to evaluate the impact of genetic polymorphisms on phenytoin pharmacokinetics and clinical outcomes in populations originating from the Middle East and North Africa region, and to characterize genotypic and allelic frequencies within the region for genetic polymorphisms assessed.

METHODS

MEDLINE (1946-3 May, 2017), EMBASE (1974-3 May, 2017), Pharmacogenomics Knowledge Base, and Public Health Genomics Knowledge Base online databases were searched. Studies were included if genotyping and analyses of phenytoin pharmacokinetics were performed in patients of the Middle East and North Africa region. Study quality was assessed using a National Institutes of Health assessment tool. A secondary search identified studies reporting genotypic and allelic frequencies of assessed genetic polymorphisms within the Middle East and North Africa region.

RESULTS

Five studies met the inclusion criteria. CYP2C9, CYP2C19, and multidrug resistance protein 1 C3435T variants were evaluated. While CYP2C9*2 and *3 variants significantly reduced phenytoin metabolism, the impacts of CYP2C19*2 and *3 variants were unclear. The multidrug resistance protein 1 CC genotype was associated with drug-resistant epilepsy, but reported impacts on phenytoin pharmacokinetics were conflicting. Appreciable variability in minor allele frequencies existed both between and within countries of the Middle East and North Africa region.

CONCLUSIONS

CYP2C9 decrease-of-function alleles altered phenytoin pharmacokinetics in patients originating from the Middle East and North Africa region. The impacts of CYP2C19 and multidrug resistance protein 1 C3435T variants on phenytoin pharmacokinetic and clinical outcomes are unclear and require further investigation. Future research should focus on the clinical outcomes associated with phenytoin therapy. PROSPERO 2017: CRD42017057850.

Genotype variability and haplotype frequency of MDR1 (ABCB1) gene polymorphism in Morocco

The multidrug resistance gene (MDR1) plays an important role in the transport of a wide range of drugs and elimination of xenobiotics from the body. Identification of polymorphisms and haplotypes in the MDR1 gene might not only help understand pharmacokinetics and pharmacodynamics of drugs, but also can help in the prediction of drug responses, toxicity, and side effects, especially, in the era of personalized medicine. We have analyzed the genotypic and haplotypic frequencies of the three most common single-nucleotide polymorphisms in the MDR1 gene in a sample of 100 unrelated healthy Moroccan subjects by polymerase chain reaction-restrictive fragment length polymorphism. The observed genotype frequencies were 43% for 1236CC, 49% for 1236CT, and 8% for 1236TT in exon 12; 49% for 2677GG, 47% for 2677GT, and 4% for 2677TT in exon 21; 39% for 3435CC, 51% 3435CT for 3435TT, and 10% for 3435TT in exon 26, respectively. We found that all polymorphisms were in Hardy-Weinberg equilibrium. Moderate linkage disequilibrium (LD) was observed between the three polymorphisms, the strongest LD in our study has been observed between C1236T and G2677T (D'=0.76; r(2)=0.45). We identified eight haplotypes, the most frequent were 1236C-2677G-3435C (53%), 1236T-2677T-3435T (21%), and 1236C-2677G-3435T (10%), respectively. Our findings might facilitate future studies on pharmacokinetics of P-glycoprotein substrate drugs and interindividual variability to drugs in Moroccan patients.

Association between SNPs in interferon regulatory factor 2 (IRF-2) gene and resistance to Aeromonas hydrophila in freshwater mussel Hyriopsis cumingii

Interferon regulatory factor 2 (IRF-2) is a multi-functional transcription factor in the IRF family exhibiting both transcriptional activating and repressing activities. In this study, an IRF-2 gene (HcIRF-2) from Hyriopsis cumingii was identified and characterized. The cDNA sequence consisted of 2688 bp, encoding a 329 amino acid-protein. The amino acid sequence had a highly conserved N-terminal DBD structure, containing characteristic repeats of six tryptophan residues. The 5'-flanking region contained several transcription regulation elements such as AP1, CdxA, HSF, NIT2 and HNF-3b. Nine SNPs were obtained through direct sequencing of HcIRF-2 from resistant and susceptible stock. Only +2365T/C SNP was significantly associated with resistance/susceptibility of H. cumingii to Aeromonas hydrophila both in genotype (P = 0.021) and allele (P = 0.006) analysis. The SNPs +2248T/C and +2365T/C were in high linkage disequilibrium, and haplotype analysis revealed that haplotype TT frequency in the resistant group was significantly higher than in the susceptible group. The mortality in +2248CC genotype individuals was significantly higher than in CT and TT genotype individuals. These results indicated that haplotype TT and genotype +2248CT and +2248GT individuals were resistant to A. hydrophila, which could make them potential markers in selective breeding of H. cumingii.