Update meta-analysis of the CYP2E1 RsaI/PstI and DraI polymorphisms and risk of antituberculosis drug-induced hepatotoxicity: evidence from 26 studies

The Impact of Tobacco Smoking and Alcohol Consumption on the Development of Gastric Cancers

Chronic infection of Helicobacter pylori is considered the principal cause of gastric cancers, but evidence has accumulated regarding the impact of tobacco smoking and alcohol consumption on the development of gastric cancers. Several possible mechanisms, including the activation of nicotinic acetylcholine receptors, have been proposed for smoking-induced gastric carcinogenesis. On the other hand, local acetaldehyde exposure and ethanol-induced mucosal inflammation have been proposed as the mechanisms involved in the development of gastric cancers in heavy alcohol drinkers. In addition, genetic polymorphisms are also considered to play a pivotal role in smoking-related and alcohol-related gastric carcinogenesis. In this review, we will discuss the molecular mechanisms involved in the development of gastric cancers in relation to tobacco smoking and alcohol consumption.

Human Cytochrome P450 1, 2, 3 Families as Pharmacogenes with Emphases on Their Antimalarial and Antituberculosis Drugs and Prevalent African Alleles

Precision medicine gives individuals tailored medical treatment, with the genotype determining the therapeutic strategy, the appropriate dosage, and the likelihood of benefit or toxicity. Cytochrome P450 (CYP) enzyme families 1, 2, and 3 play a pivotal role in eliminating most drugs. Factors that affect CYP function and expression have a major impact on treatment outcomes. Therefore, polymorphisms of these enzymes result in alleles with diverse enzymatic activity and drug metabolism phenotypes. Africa has the highest CYP genetic diversity and also the highest burden of malaria and tuberculosis, and this review presents current general information on CYP enzymes together with variation data concerning antimalarial and antituberculosis drugs, while focusing on the first three CYP families. Afrocentric alleles such as CYP2A6*17, CYP2A6*23, CYP2A6*25, CYP2A6*28, CYP2B6*6, CYP2B6*18, CYP2C8*2, CYP2C9*5, CYP2C9*8, CYP2C9*9, CYP2C19*9, CYP2C19*13, CYP2C19*15, CYP2D6*2, CYP2D6*17, CYP2D6*29, and CYP3A4*15 are implicated in diverse metabolic phenotypes of different antimalarials such as artesunate, mefloquine, quinine, primaquine, and chloroquine. Moreover, CYP3A4, CYP1A1, CYP2C8, CYP2C18, CYP2C19, CYP2J2, and CYP1B1 are implicated in the metabolism of some second-line antituberculosis drugs such as bedaquiline and linezolid. Drug-drug interactions, induction/inhibition, and enzyme polymorphisms that influence the metabolism of antituberculosis, antimalarial, and other drugs, are explored. Moreover, a mapping of Afrocentric missense mutations to CYP structures and a documentation of their known effects provided structural insights, as understanding the mechanism of action of these enzymes and how the different alleles influence enzyme function is invaluable to the advancement of precision medicine.

Association between CYP2E1 polymorphisms and colorectal cancer risk: a systematic review and meta-analysis

CYP2E1 encodes an enzyme that participates in the activation of several carcinogenic substances. Thus, numerous studies have investigated the association between CYP2E1 polymorphisms and colorectal cancer (CRC) risk, but inconclusive results have been obtained. We performed a meta-analysis to precisely evaluate the relationship of CYP2E1 rs2031920, rs3813867, and rs6413432 polymorphisms with the susceptibility to CRC. Scopus, Web of Science and PubMed databases were searched to identify eligible studies, and the association between the polymorphisms and CRC risk was then quantitatively synthesized using different genetic models. Eighteen studies with 23,598 subjects were selected for inclusion into the analysis. Significant association between rs2031920 and an increased CRC risk was observed in homozygous (OR = 1.496, 95% CI 1.177-1.901, P = 0.001), recessive (OR = 1.467, 95% CI  1.160-1.857, P = 0.001) and allele (OR = 1.162, 95% CI  1.001-1.349, P = 0.048) models. Significant association was not found for rs3813867 and rs6413432 (P > 0.05). In conclusion, our results suggest that rs2031920, but not rs3813867 and rs6413432, is associated with the risk of CRC.

Prospective study of ALDH1A1 gene polymorphisms associated with antituberculosis drug-induced liver injury in western Chinese Han population

Antituberculosis drug-induced liver injury (ATDILI) has received increasing attention globally, which may limit the effectiveness of antituberculosis (anti-TB) treatment. Many host genetic determinants of ATDILI have been identified recently. As little knowledge is currently available about the association between aldehyde dehydrogenase 1 family member A1 (ALDH1A1) polymorphisms and ATDILI, the association between their variants and the susceptibility to ATDILI was investigated. A total of 747 patients with TB treated by first-line anti-TB drugs were prospectively enrolled at West China Hospital. Genomic DNA was extracted from the peripheral blood sample of each patient and seven single-nucleotide polymorphisms (SNPs) of ALDH1A1 gene were screened and genotyped with a custom-designed 2×48-plex SNP Scan TM kit. The patients were followed up monthly to monitor the development of ATDILI. The C allele and the CA genotype of rs7852860 were significantly associated with an elevated risk for ATDILI (p = .006 and 0.005, respectively), which was consistent with the results in the dominant and additive models. No allele, genotype, or genetic model of the other six SNPs (rs3764435, rs348471, rs63319, rs610529, rs7027604, rs8187876) were found to be associated with susceptibility to ATDILI. The findings first demonstrate that rs7852860 variants in ALDH1A1 gene is associated with susceptibility to ATDILI in the Chinese Han population. Validation studies with larger sample sizes and other ethnic groups are needed to confirm the findings.

Genetic Risk Factors in Drug-Induced Liver Injury Due to Isoniazid-Containing Antituberculosis Drug Regimens

Drug-induced liver injury (DILI) is a complication of treatment with antituberculosis (TB) drugs, especially in isoniazid (INH)-containing regimens. To investigate genetic risk factors, we performed a genomewide association study (GWAS) involving anti-TB DILI cases (55 Indian and 70 European) and controls (1,199 Indian and 10,397 European). Most cases were treated with a standard anti-TB drug regimen; all received INH. We imputed single nucleotide polymorphism and HLA genotypes and performed trans-ethnic meta-analysis on GWAS and candidate gene genotypes. GWAS found one significant association (rs117491755) in Europeans only. For HLA, HLA-B*52:01 was significant (meta-analysis odds ratio (OR) 2.67, 95% confidence interval (CI) 1.63-4.37, P = 9.4 × 10^-5 ). For N-acetyltransferase 2 (NAT2), NAT2*5 frequency was lower in cases (OR 0.69, 95% CI 0.57-0.83, P = 0.01). NAT2*6 and NAT2*7 were more common, with homozygotes for NAT2*6 and/or NAT2*7 enriched among cases (OR 1.89, 95% CI 0.84-4.22, P = 0.004). We conclude HLA genotype makes a small contribution to TB drug-related DILI and that the NAT2 contribution is complex, but consistent with previous reports when differences in the metabolic effect of NAT2*5 compared with those of NAT2*6 and NAT2*7 are considered.

Genetic Predisposition to Drug-Induced Liver Injury

Identification of genetic predisposition to drug-induced liver injury (DILI) is of paramount importance. Early candidate gene studies have identified various polymorphisms in drug-metabolizing genes that infer increased DILI susceptibility. Few of these have been confirmed in more recent genome-wide association studies, which have identified several specific human leukocyte antigen (HLA) alleles. The low incidence rate of DILI, however, leads to a low positive predictive value for currently identified genetic variations, making them unsuitable for pre-prescription screening. HLA screening incorporated into clinical practice can aid the diagnostic process resulting in enhanced diagnostic accuracy and confidence.

Association of genetic polymorphisms of CYP2E1, NAT2, GST and SLCO1B1 with the risk of anti-tuberculosis drug-induced liver injury: a systematic review and meta-analysis

OBJECTIVES

The objective of this study was to investigate the association between genetic polymorphisms of N-acetyltransferase 2 (NAT2), cytochrome P450 2E1 (CYP2E1), glutathione S-transferase (GST) and solute carrier organic anion transporter family member 1B1 (SLCO1B1) and the risk of anti-tuberculosis drug-induced liver injury (ATDILI).

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

PubMed, Embase, Web of Science and Cochrane Reviews databases were searched through April 2019.

ELIGIBILITY CRITERIA

We included case-control or cohort studies investigating an association between NAT2, CYP2E1, GST or SLCO1B1 polymorphisms and the ATDILI risk in patients with tuberculosis.

DATA EXTRACTION AND SYNTHESIS

Three authors screened articles, extracted data and assessed study quality. The strength of association was evaluated for each gene using the pooled OR with a 95% CI based on the fixed-effects or random-effects model. Sensitivity analysis was performed to confirm the reliability and robustness of the results.

RESULTS

Fifty-four studies were included in this analysis (n=26 for CYP2E1, n=35 for NAT2, n=19 for GST, n=4 for SLCO1B1). The risk of ATDILI was significantly increased with the following genotypes: CYP2E1 RsaI/PstI c1/c1 (OR=1.39, 95% CI 1.06 to 1.83), NAT2 slow acetylator (OR=3.30, 95% CI 2.65 to 4.11) and GSTM1 null (OR=1.30, 95% CI 1.12 to 1.52). No significant association with ATDILI was found for the genetic polymorphisms of CYP2E1 DraI, GSTT1, GSTM1/GSTT1, SLCO1B1 388A>G and SLCO1B1 521T>C (p>0.05).

CONCLUSIONS

ATDILI is more likely to occur in patients with NAT2 slow acetylator genotype, CYP2E1 RsaI/PstI c1/c1 genotype and GSTM1 null genotype. Close monitoring may be warranted for patients with these genotypes.

Hepatocyte growth factor enhances the clearance of a multidrug-resistant Mycobacterium tuberculosis strain by high doses of conventional chemotherapy, preserving liver function

Tuberculosis (TB) is one of the deadliest infectious diseases in humankind history. Although, drug sensible TB is slowly decreasing, at present the rise of TB cases produced by multidrug-resistant (MDR) and extensively drug-resistant strains is a big challenge. Thus, looking for new therapeutic options against these MDR strains is mandatory. In the present work, we studied, in BALB/c mice infected with MDR strain, the therapeutic effect of supra-pharmacological doses of the conventional primary antibiotics rifampicin and isoniazid (administrated by gavage or intratracheal routes), in combination with recombinant human hepatocyte growth factor (HGF). This high dose of antibiotics administered for 3 months, overcome the resistant threshold of the MDR strain producing a significant reduction of pulmonary bacillary loads but induced liver damage, which was totally prevented by the administration of HGF. To address the long-term efficiency of this combined treatment, groups of animals after 1 month of treatment termination were immunosuppressed by glucocorticoid administration and, after 1 month, mice were euthanized, and the bacillary load was determined in lungs. In comparison with animals treated only with a high dose of antibiotics, animals that received the combined treatment showed significantly lower bacterial burdens. Thus, treatment of MDR-TB with very high doses of primary antibiotics particularly administrated by aerial route can produce a very good therapeutic effect, and its hepatic toxicity can be prevented by the administration of HGF, becoming in a new treatment modality for MDR-TB.

Association of PXR and CAR Polymorphisms and Antituberculosis Drug-Induced Hepatotoxicity

A combination therapy of multiple drugs including isoniazid, rifampicin, ethambutol and pyrazinamide has been proven to be an effective option for the vast majority of tuberculosis (TB) patients. However, various adverse drug reactions (ADRs) limit its merit, with anti-TB drug-induced hepatotoxicity (ATDH) being a common and sometimes severe ADR. This study aimed to investigate the association between polymorphisms in two nuclear receptor genes, pregnane X receptor (PXR) and constitutive androstane receptor (CAR), and the risk of ATDH in a Chinese population. Subjects with or without hepatotoxicity during anti-TB treatment were recruited. DNA was extracted from peripheral blood and genotypes of the selected single nucleotide polymorphisms (SNPs) were determined by using the improved multiplex ligation detection reaction technique. Three genetic models (additive, dominant, and recessive) as well as haplotype, SNP-SNP interaction analyses were used to evaluate the genetic risk of ATDH. A total of 502 subjects (203 ATDH and 299 non-ATDH) were enrolled. The results showed that the minor allele of rs7643645 and the H0010001 haplotype in PXR were associated with decreased risk of ATDH, suggesting that drug-metabolizing enzymes regulated by PXR are involved in the pathogenesis of ATDH. More studies are required to verify this result.

Association of FAM65B, AGBL4, and CUX2 genetic polymorphisms with susceptibility to antituberculosis drug-induced hepatotoxicity: validation study in a Chinese Han population

OBJECTIVE

Antituberculosis (anti-TB) drug-induced hepatotoxicity (ATDH) is a serious adverse drug reaction, and its pathogenic mechanism has not been elucidated thoroughly to date. A recent genome-wide association study reported that seven single-nucleotide polymorphisms (SNPs) in the family with sequence similarity 65, member B gene (FAM65B), ATP/GTP-binding protein-like 4 gene (AGBL4), and cut-like homeobox 2 gene (CUX2) were associated strongly with ATDH in Ethiopian patients. We validated this relationship in a Chinese Han anti-TB treatment population.

PATIENTS AND METHODS

A 1 : 2 matched case-control study was carried out of 235 ATDH cases and 470 controls. Multivariate conditional logistic regression analysis was used to estimate the association between genotypes and risk of ATDH by odds ratios with 95% confidence intervals, and weight and hepatoprotectant use were used as covariates.

RESULTS

Patients with a polymorphism at rs10946737 in the FAM65B gene were at an increased risk of moderate and severe liver injury under the dominant model (adjusted odds ratio=2.147, 95% confidence interval: 1.067-4.323, P=0.032). No other genotypes or genetic risk scores were found to be significantly related to ATDH.

CONCLUSION

This is the first study to explore and validate the relationships between seven SNPs in the FAM65B, AGBL4, and CUX2 genes and ATDH in a Chinese population. On the basis of this case-control study, SNP rs10946737 in FAM65B may be associated with susceptibility to ATDH in Chinese Han anti-TB treatment patients. Further research is warranted to explain the role of the FAM65B gene and its contribution toward individual differences in susceptibility to ATDH.

CYP genetic variants and toxicity related to anti-tubercular agents: a systematic review and meta-analysis

BACKGROUND

Treatment with anti-tuberculosis drugs may cause patients to experience serious adverse effects. Genetic factors, such as polymorphisms of CYP genes, may increase the likelihood of a patient experiencing such adverse drug reactions. In this systematic review and meta-analysis, we synthesised evidence for associations between CYP genetic variants and anti-tuberculosis drug-related toxicity outcomes.

METHODS

We searched MEDLINE, PubMed, EMBASE, BIOSIS and Web of Science to identify relevant studies. We performed meta-analyses to obtain an effect estimate for each genetic variant on each outcome, and stratified all analyses by country. We qualitatively assessed the methodological quality of the included studies.

RESULTS

We included data from 28 distinct cohorts of patients in the review. We identified many areas of concern with regard to the quality of included studies. Patients with homozygous mutant-type or heterozygous genotype at the CYP2E1 RsaI polymorphism were significantly less likely to experience hepatotoxicity than patients with homozygous wild-type genotype (odds ratio [OR] = 0.75, 95% confidence interval [CI] 0.56-1.00; p = 0.047, I2 = 58.2%). No significant differences were observed for the CYP2E1 DraI and PstI polymorphisms. For the 96-bp deletion-insertion single-nucleotide polymorphism (SNP) of the CYP2E1 gene, homozygous mutant-type significantly increased hepatotoxicity risk compared with homozygous wild-type (OR = 8.20, 95% CI 1.38-48.68, I2 = 0%); no significant difference was observed for heterozygous genotype compared with homozygous wild-type (OR = 0.77, 95% CI 0.19-3.21, I2 = 0%).

CONCLUSIONS

Generally, we identified that coverage of the association between SNPs of CYP genes and anti-tuberculosis drug-related toxicity outcomes is incomplete. We observed significant associations between the RsaI and 96-bp deletion-insertion SNPs of the CYP2E1 gene and anti-tuberculosis drug-related hepatotoxicity. We were unable to comment on the impact of ethnicity on the investigated associations, as information on participants' ethnicity was sparsely reported in the included studies.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration number: CRD42017068448.

Acarbose Use and Liver Injury in Diabetic Patients With Severe Renal Insufficiency and Hepatic Diseases: A Propensity Score-Matched Cohort Study

Background: Acarbose has been deemed contraindicated in diabetic patients with chronic kidney disease (CKD) or end-stage renal disease (ESRD), but such use is not uncommon. We tested whether this concept hold true in this population with different background hepatic diseases.

Methods: All incident diabetic patients (n = 2,036,531) with stage 5 CKD/ESRD were enrolled from Taiwan between 2017 and 2013 and divided into those without chronic liver disease (CLD), with CLD but without cirrhosis, and those with cirrhosis. Among each group, acarbose users, defined as cumulative use >30 days within the preceding year, were propensity-score matched 1:2 to non-users. Our main outcome was the development of liver injury events during follow-up.

Results: Acarbose users did not exhibit an increased incidence of liver injury during follow-up compared to non-users (hazard ratio and 95% confidence interval, 1.04 [0.88–1.25], 0.97 [0.61–1.56], and 0.71 [0.33–1.54] among those without CLD, with CLD but without cirrhosis, and those with cirrhosis, respectively), after adjusting for demographic profiles, comorbidities, potentially hepatotoxic medication use, and diabetic severity.

Conclusions: The incidence of liver injury did not increase significantly among diabetic acarbose users with severe renal insufficiency than non-users, regardless of the presence or absence of chronic liver disease. Our findings support the renaissance of acarbose as a useful adjunct in diabetic patients with stage 5 and 5D chronic kidney disease.

Analysis of the role of rs2031920 and rs3813867 polymorphisms within the cytochrome P450 2E1 gene in the risk of squamous cell carcinoma

Background

To explore the genetic effect of rs2031920 and rs3813867 polymorphisms within the cytochrome P450 2E1 (CYP2E1) gene on the risk of squamous cell carcinoma (SCC), a meta-analysis was performed.

Methods

The eligible case–control studies were obtained by database searching and screening, and the specific statistical analysis was performed with STATA 12.0 software.

Results

After the process of database searching and screening, a total of 32 case–control studies with 7435 cases and 10,466 controls were ultimately included in our meta-analysis. With regard to the rs2031920 C/T polymorphism, in comparison to controls, a reduced risk in cases of esophageal squamous cell carcinoma (ESCC) was detected for the models of allele T vs. allele C [P = 0.025, odds ratio (OR) = 0.67], carrier T vs. carrier C (P = 0.014, OR = 0.70), TT vs. CC (P = 0.029, OR = 0.65), CT vs. CC (P = 0.040, OR = 0.56), CT + TT vs. CC (P = 0.035, OR = 0.58). Similarly, a decreased SCC risk was observed for the rs3813867 G/C polymorphism in the allele, carrier, homozygote, dominant, and recessive models of overall SCC meta-analysis and “ESCC” subgroup analysis (all P < 0.05, OR < 1) and in all genetic models of “Asian” and “population-based control (PB)” subgroup analysis (all P < 0.05, OR < 1). Additionally, for the rs2031920/rs3813867 haplotype, a decreased SCC risk was also detected in the overall SCC meta-analysis under the allele, carrier, homozygote and dominant model (all P < 0.05, OR < 1) and the subgroup analysis of “PB” under the allele, carrier, and dominant models (all P < 0.05, OR < 1).

Conclusions

Our meta-analysis supports the “T” allele carrier of the CYP2E1 rs2031920 C/T polymorphism and “C” allele carrier of the rs3813867 G/C polymorphism as protective factors for ESCC patients, especially in Asian populations.

Genetic Variations Associated with Anti-Tuberculosis Drug-Induced Liver Injury

Purpose of this Review

In order to combat the development of drug resistance, the clinical treatment of tuberculosis requires the combined use of several anti-tuberculosis (anti-TB) drugs, including isoniazid and rifampicin. Combinational treatment approaches are suggested by the World Health Organization (WHO) and are widely accepted throughout the world. Unfortunately, a major side effect of the treatment is the development of anti-tuberculosis drug-induced liver injury (AT-DILI). Many factors contribute to isoniazid- and rifampicin-mediated AT-DILI and genetic variations are among the most common factors. The purpose of this review is to provide information on genetic variations associated with isoniazid- and rifampicin-mediated AT-DILI.

Recent Findings

The genetic variations associated with AT-DILI have been identified in the genomic regions within or near genes encoding proteins in the following pathways: drug metabolizing enzymes (NAT2, CYP2E1, and GSTs), accumulation of bile acids, lipids, and heme metabolites (CYP7A1, BSEP, UGTs, and PXR), immune adaptation (HLAs and TNF-α), and oxidant challenge (TXNRD1, SOD1, BACH1, and MAFK).

Summary

The information summarized in this review considers the genetic bases of risk factors contributing to AT-DILI and provides information that may help for future studies. Some of the implicated genetic variations can be used in the design of genetic tests and serve as biomarkers for the prediction of isoniazid- and rifampicin-mediated AT-DILI risk in personalized medicine.

Association and clinical utility of NAT2 in the prediction of isoniazid-induced liver injury in Singaporean patients

BACKGROUND AND AIMS

Isoniazid (INH) is part of the first-line-therapy for tuberculosis (TB) but can cause drug-induced liver injury (DILI). Several candidate single nucleotide polymorphisms (SNPs) have been previously identified but the clinical utility of these SNPs in the prediction of INH-DILI remains uncertain. The aim of this study was to assess the association between selected candidate SNPs and the risk of INH-DILI and to assess the clinical validity of associated variants in a Singaporean population.

METHODS

This was a case-control study where 24 INH-DILI cases and 79 controls were recruited from the TB control unit in a tertiary hospital. Logistic regression was used to test for the association between candidate SNPs and INH-DILI. NAT2 acetylator status was inferred from genotypes and tested for association with INH-DILI. Finally, clinical validity measures were estimated for significant variants.

RESULTS

Two SNPs in NAT2 (rs1041983 and rs1495741) and NAT2 slow acetylators (SA) were significantly associated with INH-DILI (OR (95% CI) = 13.86 (4.30-44.70), 0.10 (0.03-0.33) and 9.98 (3.32-33.80), respectively). Based on an INH-DILI prevalence of 10%, the sensitivity, specificity, positive and negative predictive values of NAT2 SA were 75%, 78%, 28% and 97%, respectively. The population attributable fraction (PAF) and number needed to test (NNT) for NAT2 SA were estimated to be 0.67 and 4.08, respectively. A model with clinical and NAT2 acetylator status provided significantly better prediction for INH-DILI than a clinical model alone (area under receiver operating characteristic curve = 0.863 vs. 0.766, respectively, p = 0.027).

CONCLUSIONS

We show the association between NAT2 SA and INH-DILI in a Singaporean population and demonstrated its clinical utility in the prediction of INH-DILI.

Influence of genetic variants on toxicity to anti-tubercular agents: a systematic review and meta-analysis (protocol)

BACKGROUND

Tuberculosis patients receiving anti-tuberculosis treatment may experience serious adverse drug reactions, such as hepatotoxicity. Genetic risk factors, such as polymorphisms of the NAT2, CYP2E1 and GSTM1 genes, may increase the risk of experiencing such toxicity events. Many pharmacogenetic studies have investigated the association between genetic variants and anti-tuberculosis drug-related toxicity events, and several meta-analyses have synthesised data from these studies, although conclusions from these meta-analyses are conflicting. Many meta-analyses also have serious methodological limitations, such as applying restrictive inclusion criteria, or not assessing the quality of included studies. Most also only consider hepatotoxicity outcomes and specific genetic variants. The purpose of this systematic review and meta-analysis is to give a comprehensive evaluation of the evidence base for associations between any genetic variant and anti-tuberculosis drug-related toxicity.

METHODS

We will search for studies in MEDLINE, EMBASE, BIOSIS and Web of Science. We will also hand search reference lists from relevant studies and contact experts in the field. We will include cohort studies, case-control studies and randomised controlled trials that recruited patients with tuberculosis who were either already established on anti-tuberculosis treatment or were commencing treatment and who were genotyped to investigate the effect of genetic variants on any anti-tuberculosis drug-related toxicity outcome. One author will screen abstracts to identify potentially relevant studies and will then obtain the full text for each potentially relevant study in order to assess eligibility. At each of these stages, a second author will independently screen/assess 10% of studies. Two authors will independently extract data and assess the quality of studies using a pre-piloted data extraction form. If appropriate, we will pool estimates of effect for each genotype on each outcome using meta-analyses stratified by ethnicity.

DISCUSSION

Our review and meta-analysis will update and add to the existing research in this field. By not restricting the scope of the review to a specific drug, genetic variant, or toxicity outcome, we hope to synthesise data for associations between genetic variants and anti-tuberculosis drug-related toxicity outcomes that have previously not been summarised in systematic reviews, and consequently, add to the knowledge base of the pharmacogenetics of anti-tuberculosis drugs.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42017068448.