Using multiplex sequence-specific amplification for physical MASP2 haplotyping [12] and the same genotype-phenotype approach that proved to be informative in our previous investigations with MBL and M-ficolin, as well as with MASP-2 in Chagas disease [14], we were able to go deeper in our investigation of lectin pathway components in the susceptibility to leprosy. The gene discussed is FCN1; the disease is Chagas disease.