In order to investigate the genetic mechanisms of resistance and susceptibility to leprosy, different approaches are used: pedigree analysis, twin studies, genetic marker analysis and investigation of candidate genes. Twin studies have shown a higher incidence of leprosy in monozygotic twins when compared to dizygotic twins, indicating an increasingly important role of genetics in susceptibility to infectious diseases. Investigation of genetic diseases can also be made through linkage studies or association. Linkage studies aim to carry out gene mapping experiments, ie to find particular genes responsible for the location of an effect positioned within the same chromosomal region. Association studies are based on comparison of allele frequencies of a particular gene between patients and healthy individuals. Such studies are commonly used in genetic epidemiology because of easy recruitment for healthy individuals (controls) or patients (cases), and most are employed in leprosy investigation, using single-base polymorphisms (SNPs) as markers of candidate genes. The SNP is a single nucleotide change which can lead to alteration in the structure and / or function of a protein. Some studies suggest that healthy controls should have been previously exposed to M. leprae without getting ill, ie, they should have been put at risk of contracting the disease.
Last date updated on June, 2014