Published online 13 January 2010
Leprosy is a chronic infectious disease of the skin and nerve that has plagued humans since biblical times. The exact mechanisms of infection and disease progression are unknown, but scientists have long suspected that host genetic factors play a role. Researchers led by Furen Zhang at the Shandong Academy of Medical Science in Jinan, Xuejun Zhang at Anhui Medical University in Hefei, both in China, and Jianjun Liu at the Genome Institute of Singapore have now conducted a genome-wide association study and identified a list of gene variants that are associated with leprosy.
The researchers sequenced the DNA of 706 patients with leprosy and 1,225 controls from eastern China. They identified variants in six genes (CCDC122, C13orf31, NOD2, TNFSF15, HLA-DR and RIPK2) that show a significant association with leprosy, as well as a seventh gene (LRRK2) that shows a trend toward an association with leprosy.
All gene variants, with the possible exception of that of LRRK2, seem to confer susceptibility to multibacillary and paucibacillary forms of leprosy, suggesting shared mechanisms underlying the development of both forms of the disease. However, several gene variants seem to be more strongly associated with the multibacillary form of the disease than the paucibacillary form.
The finding is consistent with the idea that the development of leprosy is due to genetic factors more so than environmental factors. In addition, the list of gene variants will help scientists identify people who are particularly susceptible to leprosy.