CCDC122-LACC1 gene polymorphism is associated with protection against leprosy in a population from Northeastern Brazil: a case-control study

Leprosy is a disease caused by Mycobacterium leprae and Mycobacterium lepromatosis, affecting the skin and peripheral nerves. In 2022, Brazil registered more than 19,000 new cases, considered a public health problem in the country. Interactions between the pathogen, host genetics, and the environment are factors to be considered for the development of leprosy. The CCDC122-LACC1 and IL23R genes play important roles in immune regulation. To understand the genetic basis of leprosy, this study aimed to investigate the association of SNPs belonging to the CCDC122-LACC1 and IL23R genes with leprosy in a population from northeastern Brazil. A case-control study was conducted, using confirmed leprosy patients (cases) and individuals health donors (controls). Subjects were recruited from Northeastern states of Brazil, with a total sample size 952 (562 in Alagoas and 390 in Bahia and Pernambuco, being 488 samples from cases (298 in Alagoas and 190 in Bahia and Pernambuco) and 464 controls (264 in Alagoas and 200 in Bahia and Pernambuco). Genotyping of the SNPs CCDC122-LACC1 and IL23R was performed using real-time PCR (Taqman, StepOne Plus™). Associations were quantified using odds ratios with 95% confidence intervals, and were performed in the R environment (v.3.4.4). The results demonstrated that SNP CDC122-LACC1 was associated with protection against leprosy in the population of Alagoas (ORCC = 0.58, p = 0.02), and in the combined analysis of the populations of Northeastern Brazil (ORCC = 0.65, p = 0.02), which was also associated with the multibacillary operational classification in the populations mentioned above. While analyzing the IL23R polymorphism, no association with leprosy was observed in any of the analyses performed in the study populations, and no association was identified with the operational classifications of the disease. The SNP rs4942254 in the CCDC122-LACC1 gene was associated with protection against development of leprosy.