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

The major histocompatibility complex class I chain-related gene A (MICA)-TM exon 5 trinucleotide polymorphism, the MICB-C1_2_A intron 1 dinucleotide polymorphism and the tetranucleotide polymorphism C1_4_1 located in the major histocompatibility complex class I region on chromosome 6 were shown to influence various chronic inflammatory conditions. We investigated the association of these microsatellite polymorphisms with chronic periodontitis, a highly prevalent oral inflammatory disease in 389 periodontitis patients and 771 healthy controls with South German genetic background. Genotyping of the MICA-TM, MICB-C1_2_A and C1_4_1 microsatellite polymorphisms was performed by PCR amplification and fragment analysis. Global frequency distribution of MICB-C1_2_A (P = 0.006) and C1_4_1 (P = 0.028) alleles was significantly different between both study groups. Allele-specific analysis revealed that the MICA-TM allele A5 was more prevalent among male periodontitis patients [P = 0.0001; odds ratio (OR) 2.17, 95% confidence interval (CI) 1.55-3.03]. In C1_4_1 allele, three was significantly higher in healthy controls (P = 0.006; OR 0.74, 95% CI 0.60-0.91). Two haplotypes (MICA:A5-C1_4_1:5; P = 0.002; OR 2.63, 95% CI 1.46-4.74 and MICB:CA16-C1_4_1:3; P = 0.014; OR 0.68, 95% CI 0.50-0.92) showed significant differences between periodontitis patients and controls. The MICA-TM, MICB-C1_2_A and C1_4_1 microsatellite polymorphism seem to influence the individual susceptibility to chronic periodontitis in patients with German genetic background.