A rare variant at 11p13 is associated with tuberculosis susceptibility in the Han Chinese population

Gene expression pattern analysis using dual-color RT-MLPA and integrative genome-wide association studies of eQTL for tuberculosis suscepitibility

Background

When infected with Mycobacterium tuberculosis, only a small proportion of the population will develop active TB, and the role of host genetic factors in different TB infection status was not fully understood.

Methods

Forty-three patients with active tuberculosis and 49 with latent tuberculosis were enrolled in the prospective cohort. Expressing levels of 27 candidate mRNAs, which were previously demonstrated to differentially expressed in latent and active TB, were measured by dual color reverse transcription multiplex ligation dependent probe amplification assay (dcRT-MLPA). Using expression levels of these mRNAs as quantitative traits, associations between expression abundance and genome-wild single nucleotide polymorphisms (SNPs) were calculated. Finally, identified candidate SNPs were further assessed for their associations with TB infection status in a validation cohort with 313 Chinese Han cases.

Results

We identified 9 differentially expressed mRNAs including il7r, il4, il8, tnfrsf1b, pgm5, ccl19, il2ra, marco and fpr1 in the prospective cohort. Through expression quantitative trait loci mapping, we screened out 8 SNPs associated with these mRNAs. Then, CG genotype of the SNP rs62292160 was finally verified to be significantly associated with higher transcription levels of IL4 in LTBI than in TB patients.

Conclusion

We reported that the SNP rs62292160 in Chinese Han population may link to higher expression of il4 in latent tuberculosis. Our findings provided a new genetic variation locus for further exploration of the mechanisms of TB and a possible target for TB genetic susceptibility studies, which might aid the clinical decision to precision treatment of TB.

Polymorphisms in ERAP1 and ERAP2 Genes Are Associated With Tuberculosis in the Han Chinese

Single nucleotide polymorphisms (SNPs) in the endoplasmic reticulum aminopeptidase (ERAP1 and ERAP2) genes are associated with the pathogenesis of bacterial and viral infections. To search for the variations in the ERAP1 and ERAP2 genes associated with tuberculosis (TB), 449 TB cases and 435 healthy individuals of the Han population in the Yunnan province of China were included in the present study. Eleven SNPs of ERAPs were genotyped using the SNaPshot SNP assay. Allelic, genotypic, and haplotypic association analyses were performed between the TB and control groups. Furthermore, stratification analyses among pulmonary TB (PTB), extrapulmonary TB (EPTB), and healthy controls; and initial treatment TB (ITTB), retreatment TB (RTB), and healthy controls were also performed. The TT genotype of rs26618 in ERAP1 exhibited a protective factor for TB, compared with the role of the CC/CT genotype (P = 0.003; OR = 1.490, 95% CI: 1.140-1.940). In ERAP2, the frequency of the G allele of rs2549782 was higher in the case group than in the control group (0.491 vs. 0.417, P = 0.002, OR = 1.350, 95% CI: 1.118-1.631), and the TT genotype exhibited a protective factor for TB, compared with the role of the GG/GT genotype (P = 0.001; OR = 1.650, 95% CI: 1.230-2.220). The frequency of the C allele of rs1056893 was higher in the case group than in the control group (0.468 vs. 0.394, P = 0.002, OR = 1.350, 95% CI: 1.118-1.631), and the genotype exhibited a difference in the log-additive model (P = 0.002; OR = 1.350, 95% CI: 1.120-1.630). The frequencies of the haplotype rs27037-rs27044-s30187-rs26618-rs26653-rs3734016-GCCCGC in ERAP1 (0.290 vs. 0.240, P-adj = 0.028, OR = 1.320, 95% CI: 1.063-1.638) and the haplotypes rs2549782-rs2248374-rs2287988-rs1056893-GTAGC in ERAP2 (0.446 vs. 0.348, P-adj = 4.80E-05, OR = 1.510, 95% CI: 1.246-1.829) was higher in the TB groups, while the frequencies of the haplotypes rs2549782-rs2248374-rs2287988-rs1056893-TAGAT (0.478 vs. 0.539, P-adj = 0.020, OR = 0.782, 95% CI: 0.649-0.943) were lower in the TB groups. The allelic and genotypic associations were also investigated in the subsequent stratification between the PTB, EPTB and control groups as well as between the ITTB, RTB, and control groups. In conclusion, variations in ERAP1 and ERAP2 genes were identified to be associated with TB in the Han Chinese population.

Evaluation of the Host Genetic Effects of Tuberculosis-Associated Variants Among Patients With Type 1 and Type 2 Diabetes Mellitus

Background

Understanding the link between tuberculosis (TB) and diabetes is increasingly important as public health responds to the growing global burden of noncommunicable diseases. Genetic association studies have identified numerous host genetic variants linked to TB; however, potential host genetic mechanisms linking TB and diabetes remain unexplored.

Methods

We used genetic and phenotypic data from the UK Biobank to evaluate the association of 6 previously reported TB-related host genetic variants (genome-wide significant associations from published studies) with diabetes. The study included 409692 adults of European ancestry including 2177 with type 1 diabetes mellitus (T1DM) and 13976 with type 2 diabetes mellitus (T2DM), defined by ICD-10 diagnosis codes.

Results

Of the 6 TB-associated single nucleotide polymorphisms (SNPs), 2 were associated with T1DM and 3 with T2DM, after adjusting for age, sex, body mass index, smoking, alcohol use, and population structure. After correction for multiple testing, SNPs rs2894257 and rs3135359 (HLA-DRA-DQA1) were associated with T1DM (rs2894257: odds ratio [OR], 1.32; 95% confidence interval [CI], 1.21–1.45; rs3135359: OR, 1.72; 95% CI, 1.57–1.88) and T2DM (rs2894257: OR, 1.11; 95% CI, 1.08–1.15; rs3135359: OR, 1.06; 95% CI, 1.025–1.096). The associations with T2DM weakened for rs2894257 and rs3135359 after further exclusion of probable T1DM cases defined by International Statistical Classification of Diseases and Related Health Problems (ICD-10) codes. SNP rs4733781 on chromosome 8 (ASAP1 gene) was associated with T2DM after exclusion of T1DM cases.

Conclusions

Our findings suggest that common host genetic effects may play a role in the molecular mechanism linking TB and diabetes. Future large genetic studies of TB and diabetes should focus on developing countries with high burdens of infectious and chronic diseases.

2'-5'-Oligoadenylate synthetase 1 polymorphisms are associated with tuberculosis: a case-control study

Background

2′-5′-Oligoadenylate synthetase 1 (OAS1) plays an important role in inflammatory immune reactions. OAS1 polymorphisms have been associated with increased susceptibility to various diseases. We investigated the association of polymorphisms in OAS1 with tuberculosis (TB).

Methods

A total of 1215 TB cases and 1114 healthy controls were enrolled from two independent studies. Genotyping was conducted using the improved multiplex ligase detection reaction (iMLDR) method. Associations between OAS1 polymorphisms (rs2240190, rs1131454, 10,774,671 and 11,066,453) and TB risk were established based on distributions of allelic frequencies using different genetic models.

Results

Significant association was observed between rs10774671, rs1131454 and TB. In the initial study, the G allele of rs10774671 was a significantly protective factor against TB (P = 0.006) and the genotype of GG differed significantly between TB patients and controls under the codominant model (P = 0.008) after Bonferroni correction. In the validation study, we also observed that the rs10774671 G allele (P = 0.001) and GG genotype (P = 0.001) were associated with TB. In addition, we found that the rs1131454 G allele (P = 0.004) and GG genotype (P = 0.001) were protective against TB in the Chinese Han population.

Conclusions

We report novel associations of polymorphisms in OAS1 with TB in the Chinese Tibetan and Han populations. Similar studies in different populations and functional studies are warranted to confirm our results.

Discovery of susceptibility loci associated with tuberculosis in Han Chinese

Genome-wide association studies (GWASs) have revealed the worldwide heterogeneity of genetic factors in tuberculosis (TB) susceptibility. Despite having the third highest global TB burden, no TB-related GWAS has been performed in China. Here, we performed the first three-stage GWAS on TB in the Han Chinese population. In the stage 1 (discovery stage), after quality control, 691 388 SNPs present in 972 TB patients and 1537 controls were retained. After replication on an additional 3460 TB patients and 4862 controls (stages 2 and 3), we identified three significant loci associated with TB, the most significant of which was rs4240897 (logistic regression P = 1.41 × 10-11, odds ratio = 0.79). The aforementioned three SNPs were harbored by MFN2, RGS12 and human leukocyte antigen class II beta chain paralogue encoding genes, all of which are candidate immune genes associated with TB. Our findings provide new insight into the genetic background of TB in the Han Chinese population.