Impact of MICA-TM, MICB-C1_2_A and C1_4_1 microsatellite polymorphisms on the susceptibility to chronic periodontitis in Germany

Association of MICA gene Exon-5 polymorphism in oral submucous fibrosis

OBJECTIVE

The present study was conducted to explore the allele frequencies of MICA gene Exon-5 transmembrane and to measure the circulatory MICA levels in various histologic grades of patients with oral submucous fibrosis (OSF) compared to healthy individuals.

STUDY DESIGN

We enrolled a total of 595 patients for this cross-sectional study and divided them into 2 groups: healthy controls (n = 320) and patients with OSF (n = 275). Further, patients with OSF were subdivided based on their histologic gradings. The genomic DNA was extracted followed by a polymerase chain reaction and genotyping using the ABI Prism DNA Sequencer (ThermoFisher Scientific, Inc., Waltham, MA, USA).

RESULTS

Our study showed that the A5 allele of the MICA gene in the Exon-5 region conferred significant risk for patients with OSF. With reference to the histologic gradings of OSF, we found that the MICA gene conferred statistically significant risk among patients with grade III OSF. On the other hand, the A8 allele of MICA gene in the Exon-5 region conferred significant protection among the overall OSF cohort and in the grade III of histologic grade. Finally, the circulatory human MICA levels were found to have a stepwise increase from grade I toward grade III in patients with OSF.

CONCLUSION

Our results suggested that the A5 allele in MICA might confer risk for the progression of OSF among the South Indian ethnic population.

Host genetics role in the pathogenesis of periodontal disease and caries

BACKGROUND

This study aimed to produce the latest summary of the evidence for association of host genetic variants contributing to both periodontal diseases and caries.

MATERIALS AND METHODS

Two systematic searches of the literature were conducted in Ovid Medline, Embase, LILACS and Cochrane Library for large candidate gene studies (CGS), systematic reviews and genome-wide association studies reporting data on host genetic variants and presence of periodontal disease and caries.

RESULTS

A total of 124 studies were included in the review (59 for the periodontitis outcome and 65 for the caries outcome), from an initial search of 15,487 titles. Gene variants associated with periodontitis were categorized based on strength of evidence and then compared with gene variants associated with caries. Several gene variants showed moderate to strong evidence of association with periodontitis, although none of them had also been associated with the caries trait.

CONCLUSIONS

Despite some potential aetiopathogenic similarities between periodontitis and caries, no genetic variants to date have clearly been associated with both diseases. Further studies or comparisons across studies with large sample size and clear phenotype definition could shed light into possible shared genetic risk factors for caries and periodontitis.

Salivary biomarkers in association with periodontal parameters and the periodontitis risk haplotype

Genetic factors play a role in periodontitis. Here we examined whether the risk haplotype of MHC class III region BAT1-NFKBIL1-LTA and lymphotoxin-α polymorphisms associate with salivary biomarkers of periodontal disease. A total of 455 individuals with detailed clinical and radiographic periodontal health data were included in the study. A 610 K genotyping chip and a Sequenom platform were used in genotyping analyses. Phospholipid transfer protein activity, concentrations of lymphotoxin-α, IL-8 and myeloperoxidase, and a cumulative risk score (combining Porphyromonas gingivalis, IL-1β and matrix metalloproteinase-8) were examined in saliva samples. Elevated IL-8 and myeloperoxidase concentrations and cumulative risk scores associated with advanced tooth loss, deepened periodontal pockets and signs of periodontal inflammation. In multiple logistic regression models adjusted for periodontal parameters and risk factors, myeloperoxidase concentration (odds ratio (OR); 1.37, P = 0.007) associated with increased odds for having the risk haplotype and lymphotoxin-α concentration with its genetic variants rs2857708, rs2009658 and rs2844482. In conclusion, salivary levels of IL-8, myeloperoxidase and cumulative risk scores associate with periodontal inflammation and tissue destruction, while those of myeloperoxidase and lymphotoxin-α associate with genetic factors as well.

MIC gene polymorphism and haplotype diversity in Zhuang nationality of Southern China

Zhuang ethnic minority is the largest minority group in China. Here, we report for the first time the polymorphisms of MICA and MICB in a healthy Zhuang population of 209 unrelated individuals. Using polymerase chain reaction-sequence specific priming (PCR-SSP) and sequencing-based typing (PCR-SBT), 13 MICA-sequence alleles and 5 MICA-STR alleles, as well as 11 MICB alleles were detected, among which MICA(∗)010, MICA(∗)A5 and MICB(∗)005:02 were the most frequent alleles. Linkage disequilibria was investigated and the most common two-locus haplotypes were MICB(∗)005:02-MICA(∗)010 and MICB(∗)014-MICA(∗)045. These results suggest informative genetic markers for investigating origins and evolution of MHC class I region haplotypes in Zhuang population.

Major histocompatibility complex class I chain-related gene polymorphisms: associated with susceptibility to Kawasaki disease and coronary artery aneurysms

BACKGROUND

Kawasaki disease (KD) involves a complex interaction of immunoinflammatory process, cytokine activation, and genetic factors. We aimed to investigate whether genetic variations in a major histocompatibility complex (MHC) class could be used as markers of susceptibility in KD and coronary artery aneurysm lesions (CALs).

METHODS

Individuals were divided into following groups: (1) normal controls; (2) KD with CAL; (3) KD without CAL. Polymorphisms for MHC class I chain-related genes A (MICA) (rs2301747, rs2256184, rs2848716), MICB (rs2855804, rs3132464, rs2516400), BAT3 (rs750332), MSH5 (rs1150793), and chromosome 6 open reading frame 27 (C6orf27, rs707928) were genotyped with polymerase chain reaction and the TaqMan(®) allelic discrimination assay. Genotypes, alleles, and haplotype in each group were compared.

RESULTS

Genotype and allele frequency of MICB*rs2516400 polymorphisms in each group were significantly different. MICB (rs2516400)*C-related genotypes/alleles are correlated with development of KD and CAL. Proportions of rs2516400*TT/TC/CC were (1) 1/39/60%, (2) 0/0/100%, and (3) 0/0/100%. Other single-nucleotide polymorphisms were not associated with KD susceptibilities. Haplotypes (rs2301747-rs2256184-rs2848716-rs2855804-rs3132464-rs2516400-rs750332-rs1150793-rs707928) G-G-G-C-T-C-T-A-A, C-A-G-T-T-C-T-A-A, and G-G-G-C-C-C-T-A-A were associated with higher susceptibilities for KD. The G-G-G-T-T-T-T-G-G and C-G-G-T-T-T-T-A-A haplotypes were associated with lower susceptibilities.

CONCLUSION

MICB*rs2516400 polymorphisms and some MHC class I-related haplotypes are associated with KD susceptibility. MICB and MHC class I genetic variations might contribute to the pathogenesis of KD and CAL.