Polymorphisms In Mitochondrial Ribosomal Protein S5 (Mrps5) Are Associated With Leprosy Risk In Chinese

Leprosy is an infectious disease caused by Mycobacterium leprae (M. leprae), with about 210,000 new cases per year worldwide. Although numerous risk loci have been uncovered by genome-wide association studies, the effects of common genetic variants are relatively modest. To identify possible new genetic locus involved in susceptibility to leprosy, whole exome sequencing was performed for 28 subjects including 14 patients and 12 unaffected members from 8 leprosy-affected families as well as another case and an unrelated control, and then the follow-up SNP genotyping of the candidate variants was studied in case-control sample sets. A rare missense variant in mitochondrial ribosomal protein S5 (MRPS5), rs200730619 (c. 95108402T>C [p. Tyr137Cys]) was identified and validated in 369 cases and 270 controls of Chinese descent (P-adjusted = 0.006, odds ratio [OR] = 2.74) as a contributing factor to leprosy risk. Moreover, the mRNA level of MRPS5 was downregulated in M. leprae sonicate-stimulated peripheral blood mononuclear cells. Our results indicated that MRPS5 may be involved in leprosy pathogenesis. Further studies are needed to determine if defective MRPS5 could lead to impairment of energy metabolism of host immune cells, which could further cause defect in clearing M. leprae and increase susceptibility to infection.Author summaryLeprosy is an infectious disease caused by Mycobacterium leprae, and the global new case detection rate remains high after the introduction of multidrug therapy for almost four decades with a significant reduction in prevalence. The identification of possible new genetic loci involved in susceptibility to leprosy is needed to the further understanding of the pathogenesis of leprosy and help achieve final elimination of leprosy. Here, we report a potential leprosy-associated variant in mitochondrial ribosomal protein S5 (MRPS5) by using whole exome sequencing performed on 28 individuals including 8 leprosy-affected families and the follow-up SNP genotyping of the candidate variant in case-control sample sets. We provide genetic evidence and expression data suggesting that MRPS5 is a novel leprosy-associated gene which may play an important role in the pathogenesis of leprosy.