Age-Related Hearing Impairment Associated NAT2, GRM7, GRHL2 Susceptibility Gene Polymorphisms and Haplotypes in Roma and Hungarian Populations

Age-related hearing impairment (ARHI) is the most frequent sensory disease in the elderly, which is caused by an interaction between genetic and environmental factors. Here we examined the ethnic differences, allele and genotype frequencies of the NAT2, GRM7, and GRHL2 genes pooled samples of healthy Hungarian and healthy and hearing impaired Roma people. Study populations of healthy Hungarian and Roma subjects were characterized for the rs1799930 NAT2, rs11928865 GRM7, rs10955255, rs13263539, and rs1981361 GRHL2 polymorphisms and deaf Roma subjects were characterized for the rs1799930 NAT2, rs13263539, and rs1981361 GRHL2 using a PCR-RFLP method. We found significant differences in minor allele frequencies for GRHL2 rs13263539 and rs1981361 polymorphism between healthy Roma and Hungarian samples (37.9% vs. 51.0% and 43.6% vs. 56.2%, respectively; p < 0.05). The differences of homozygous genotype of GRHL2 rs13263539 and rs1981361 variants, values were also significantly different (13.0% vs. 25.3% and 16.5 vs. 32.3%; p < 0.05). The NAT2 rs1799930 homozygous genotype was 14.0% in healthy Romas and 7.7% in Hungarians, while the minor A allele frequency was 38.0% and 26.7% in Roma and Hungarian population, respectively (p < 0.05). Furthermore, the frequency of GGT, GAC and GAT haplotypes was significantly higher in the Hungarian population than in healthy Roma (1.87 vs. 4.47%, 0.91 vs. 2.07% and 1.15 vs. 5.51%, respectively; p < 0.008). Present study revealed significant interethnic differences in allele polymorphisms of NAT2, GRM7 and GRHL2 exhibit quite marked ethnic differences in Roma populations that might have important implications for the preventive and therapeutic treatments in this population.