Hum. Genet：姚永刚等麻风病遗传易感性获新证据

近日，昆明动物所科研人员对麻风病的最新研究发现，线粒体在麻风发病过程中具有一定的作用，并且不同人群的易感遗传变异存在差异。这两项研究成果为进一步了解麻风病的遗传易感提供了新证据，也为其他传染性疾病的研究提供一定的参考。这两项研究成果分别发表在《公共科学图书馆—综合》(PLoS ONE)和《人类遗传学》(Human Genetics)上。

据悉，麻风病是由麻风分枝杆菌感染引起的一种慢性传染病，患者通常出现肢端残疾、畸形、失明甚至毁容等症状，受到社会的歧视。但是，其具体的致病机理至今尚不清楚。

近年来，研究发现麻风病的发生与个体的遗传背景和免疫状态有关，接触到麻风分枝杆菌的个体只有少数人发病。另外，麻风病患者多来自贫穷和不发达地区，营养低下会影响麻风杆菌的易感性。云南省是我国麻风病重灾区，具有流行时间长、发病率高、流行范围广等特点。

为此，中科院昆明动物研究所联合昆明医学院第一附属医院和玉溪市疾病预防控制中心，总结了玉溪地区57年来麻风流行情况，并开展麻风病流行和遗传易感性研究工作。

昆明动物所博士研究生王东在姚永刚研究员的指导下，通过对玉溪地区麻风患者和正常对照个体线粒体DNA遗传背景的分析，发现线粒体DNA遗传背景不影响麻风发病，但瘤型麻风患者中具有更高的线粒体DNA拷贝数，提示线粒体在麻风发病过程中具有一定的作用。

同时，他们还针对近期文献报道与麻风相关的MRC1和IFNG基因进行了基因分型，在来自玉溪地区的527例麻风病人和583例对照人群中，没有验证到这两个基因的易感位点，反而在这两个基因上发现其他的易感位点。分析结果显示MRC1基因的rs692527和rs34856358位点变异与少菌型麻风显著相关，IFNG基因rs3138557位点变异与多菌型麻风显著相关。该结果支持MRC1和IFNG基因是麻风的易感基因，但提示不同人群的易感遗传变异存在差异。

doi:10.1007/s00439-012-1153-7
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Original InvestigationGenetic variants of the MRC1 gene and the IFNG gene are associated with leprosy in Han Chinese from Southwest China

Dong Wang, Jia-Qi Feng, Yu-Ye Li, Deng-Feng Zhang, Xiao-An Li, Qing-Wei Li and Yong-Gang Yao

Leprosy is an ancient infectious disease, with over 200,000 affected people (mainly in Asia and Africa) being registered annually. Genetic factors may confer susceptibility to this disease. In the present study, we genotyped 12 genetic variants of the MRC1 gene and the IFNG gene in 527 Han Chinese with leprosy and 583 healthy individuals from Yunnan, China, to discern potential association of these two genes with leprosy. In particular, we aimed to validate the recently reported association of MRC1 variant rs1926736 (p.G396S) and IFNG variant rs2430561 (+874 T>A) with leprosy, which were initially observed in Vietnamese and Brazilian populations, respectively. Our results failed to confirm the reported association between variants rs1926736 and rs2430561 and leprosy in Han Chinese. However, we found that variants rs692527 (P = 0.022) and rs34856358 (P = 0.022) of the MRC1 gene were associated with paucibacillary leprosy, and rs3138557 of the IFNG gene was significantly associated with multibacillary leprosy. The exact role of the MRC1 gene and the IFNG gene in leprosy awaits future study.