牛皮癣是一种常见的发炎性皮肤病，2%的世界人口会罹患这种疾病。在12月在线出版的《自然—遗传学》（Nature Genetics）期刊上，一篇论文报告说，携带多余版本的小抗菌蛋白质编码基因的个体患牛皮癣的风险更高。
最近，科学家们发现，部分个体携带两个版本以上的某种基因，也有一些人携带得更少，他们推测这些“复制数字变异”可能会影响个体患上牛皮癣的风险。在某个区域，某些种群的个体携带了2~12个基因版本，这些基因负责编码分泌性蛋白质β-防卫素。因为β-防卫素是在皮肤上被表达，所以当感染或其他环境触发因子出现时会引发炎症。
John Armour和同事推测，β-防卫素基因复制数量的变化可能影响了牛皮癣出现的风险。在包括荷兰和德国科学家所作的两个独立研究中，作者发现从平均数量上看，牛皮癣患者比正常人拥有更多版本的β-防卫素基因。
β-防卫素是先天性免疫系统的组成部分，能保护个体免遭感染的侵袭。它们能迅速引导针对感染或受伤的反应，并触发其他蛋白质如白细胞介素IL-8、IL-18和IL-20的释放，促成炎症，这就是牛皮癣。（来源：科学时报 王丹红／编译）
原始出处:
Nature Genetics
Published online: 2 December 2007 | doi:10.1038/ng.2007.48
Psoriasis is associated with increased -defensin genomic copy number
Edward J Hollox1, Ulrike Huffmeier2, Patrick L J M Zeeuwen3, Raquel Palla4, Jesús Lascorz2, Diana Rodijk-Olthuis3, Peter C M van de Kerkhof3, Heiko Traupe5, Gys de Jongh3, Martin den Heijer6, André Reis2, John A L Armour4,7 & Joost Schalkwijk3,7
Psoriasis is a common inflammatory skin disease with a strong genetic component. We analyzed the genomic copy number polymorphism of the -defensin region on human chromosome 8 in 179 Dutch individuals with psoriasis and 272 controls and in 319 German individuals with psoriasis and 305 controls. Comparisons in both cohorts showed a significant association between higher genomic copy number for -defensin genes and risk of psoriasis.
Department of Genetics, University of Leicester, Leicester LE1 7RH, UK.
Institute of Human Genetics, Friedrich Alexander University Erlangen Nuremberg, 91054 Erlangen, Germany.
Department of Dermatology, Radboud University Nijmegen Medical Centre, Nijmegen Centre for Molecular Life Sciences, 652 GA Nijmegen, The Netherlands.
Institute of Genetics, University of Nottingham, Nottingham NG7 2UH, UK.
Department of Dermatology, University of Münster, NG7 2UH Münster, Germany.
Department of Endocrinology and Department of Epidemiology and Biostatistics, Radboud University Nijmegen Medical Centre, 6500 HB Nijmegen, The Netherlands.
These authors contributed equally to this work.
Correspondence to: John A L Armour4,7 e-mail: john.armour@nottingham.ac.uk
