Análise da influência de fatores genéticos na suscetibilidade à hanseníase na população da microrregião de Almenara, Minas Gerais

Abstract

Leprosy is an infectious disease that presents a large spectrum of clinical manifestations. This variation is correlated to the level of the host immune response to the Mycobacterium leprae, which in turn is influenced by the individual genetic background. The majority of genes and genomic regions associated with susceptibility/resistance to leprosy are related to the production of cytokines and other important molecules in the immunological pathways. However, although this hypothesis is widely accepted, different studies with distinct populations have often discordant or controversial results. For this reason, it is necessary to perform additional studies, with different designs and populations, aiming to replicate and validate the results already found. The objective of this study was to analyze the influence of single nucleotide polymorph isms (SNP) on the susceptibility to leprosy among the population from the microregion of Almenara, Minas Gerais. For this purpose, it was conducted a family based study and the analysis was performed using the Transmission Disequilibrium Test (TDT). Genetic polymorphisms of TLR1, NOD2, LTA4H, IFNG and IL10 genes were analyzed. The sample was composed of 125 nuclear families of leprosy cases from the cities of Almenara, Felisburgo, Jacinto, Jordania, Palmopolis and Rubim, with a total of 447 individuals. Meta-analysis were carried out to define consensus association estimates for the available studies about TLR1, IFNG and IL10 genes. The analysis of transmission disequilibrium identified a statistically significant association between the TLR1 rs4833095 and rs5743618 SNPs and the leprosy per se, and the G and T alleles, respectively, were associated to the disease susceptibility. The analysis of the transmission of these markers also indicated that the G/T and A/G haplotypes (rs4833095/rs5743618) were associat ed to susceptibility and resistance to leprosy, respectively. No significant associations were found between the alleles and haplotypes of the other polymorphisms and the disease. Meta-analysis showed statistically significant results for the TLR1 rs4833095 and rs5743618, IFNG rs2430561 and IL10 rs1800871 SNPs. The results confirmed the role of TLR1 gene on the regulation of immune response to the M. leprae and indicate that other studies will be required for conclusive results to the other genes analyzed.