CHANGED MAPK1 POLYMORPHISM IN RESIDENTS LIVING IN THE COAL-BURNING TYPE OF ENDEMIC FLUOROSIS AREA IN GUIZHOU PROVINCE, PEOPLE'S REPUBLIC OF CHINA

Based on the results obtained in our group showing that chronic fluorosis can influence the expression of the extracellular signal-regulated protein kinase 1 and 2 (ERK1/2) in the mitogen-activated protein kinase (MAPK) pathway, we further investigated whether the multiple single nucleotide polymorphisms (SNPs) of the MAPK1 gene (encoding ERK1/2) were connected to the injuries caused by long-term exposure to the fluoride ion. The presence of dental and skeletal fluorosis and the genotypes and imputed SNPs of the MAPK1 gene were determined in a total of 222 residents from the coal-burning type of endemic fluorosis area in Guizhou Province, People's Republic of China. The frequencies of the genotypes of the rs743409 and rs7286558 alleles were detected with the Hardy Weinberg equilibrium. The results showed that in the population living in the area of endemic fluorosis, the most frequently expressed genotype of the rs743409 allele was TT and that for the rs7286558 allele it was GG. A significant correlation was found between the female gender and presence of the CT and TT genotypes of rs743409. The incidence of fluorosis was: dental fluorosis: female 72.2%, male 71.9%; skeletal fluorosis: female 32.1%, male 28.8%. Interestingly, among these clinical manifestations, skeletal fluorosis was significantly connected with the GG genotype of rs7286558. The results suggested that sensitivity to skeletal fluorosis in the residents living in the coal-burning type of endemic fluorosis area might be associated with the modified gene polymorphism of the MAPK1 gene.