Rare and common variants in CARD14, an epidermal regulator of NF-kappaB, in psoriasis. Homo sapiens

Psoriasis is a common inflammatory disorder of the skin and other organs. We have determined that mutations in CARD14, encoding an NF-kB activator within skin epidermis, account for PSORS2. Here we describe fifteen additional rare, missense variants in CARD14, their distribution in seven psoriasis cohorts (>6,000 cases and >4,000 controls), and their effects on NF-kB activation and the transcriptome of keratinocytes. There was an excess of rare variants within CARD14 in cases versus controls (burden test p-value = 0.0015). Some variants were only seen in a single case and included putative pathogenic mutations (c.424G>A [p.Glu142Lys], c.425A>G [p.Glu142Gly]) and the generalized pustular psoriasis mutation, c.413A>C (p.Glu138Ala), that lie within the coiled-coil domain of CARD14. The c.349G>A (p.Gly117Ser) familial psoriasis mutation was present at a frequency of 0.0005 in cases of European ancestry. CARD14 variants led to a range of NF-kB activities, with putative pathogenic variants leading to levels >2.5-fold higher than wildtype CARD14. Two variants (c.511C>A [p.His171Asn] and c.536G>A [p.Arg179His]) required stimulation with TNF-a to achieve significant increases in NF-kB levels. Transcriptome profiling of wildtype and variant CARD14 transfectants in keratinocytes differentiated likely pathogenic mutations from neutral variants such as polymorphisms. Over 20 CARD14 polymorphisms were also genotyped and meta-analysis revealed association of psoriasis with rs11652075 (c.2458C>T/p.Arg820Trp; p-value = 2.1x10-6). In the two largest psoriasis cohorts, evidence for association increased when rs11652075 was conditioned on HLA-Cw*0602 (PSORS1). These studies contribute to our understanding of the genetic basis of psoriasis and illustrate the challenges faced in identifying pathogenic variants in common disease. Overall design: Keratinocytes were transfected with wildtype Cardsh or one of 16 Card14 mutations (17 total samples). The cells were collected and RNA extracted to determine the effect of these mutations compared to wildtype Card14. No replicates are included.

银屑病（Psoriasis）是一种常见的皮肤及其他器官炎症性疾病。本研究证实，编码皮肤表皮内核因子κB（NF-κB）激活蛋白的CARD14基因发生突变，是PSORS2型银屑病的致病原因。本文报道了CARD14基因中另外15种罕见错义变异，分析了它们在7个银屑病队列（超过6000例患者、超过4000例对照）中的分布情况，以及它们对核因子κB（NF-κB）激活及角质形成细胞（keratinocytes）转录组的影响。与对照组相比，病例组中CARD14基因内的罕见变异呈现富集趋势，变异负担检验（burden test）P值为0.0015。部分变异仅在单例患者中被检出，其中包括疑似致病突变：c.424G>A [p.Glu142Lys]、c.425A>G [p.Glu142Gly]，以及位于CARD14卷曲螺旋结构域（coiled-coil domain）内的泛发性脓疱型银屑病致病突变c.413A>C（p.Glu138Ala）。欧洲血统患者中，c.349G>A（p.Gly117Ser）家族性银屑病突变的检出频率为0.0005。CARD14基因变异可导致不同程度的核因子κB（NF-κB）活性变化，疑似致病变异的NF-κB活性水平较野生型CARD14升高2.5倍以上。有两种变异（c.511C>A [p.His171Asn]和c.536G>A [p.Arg179His]）需经肿瘤坏死因子-α（TNF-α）刺激后，才可使NF-κB水平出现显著升高。通过对转染野生型及变异型CARD14的角质形成细胞（keratinocytes）进行转录组谱分析（transcriptome profiling），可将疑似致病突变与多态性（polymorphisms）等中性变异区分开来。本研究还对超过20种CARD14基因多态性进行了基因分型，荟萃分析（meta-analysis）结果显示，rs11652075（c.2458C>T/p.Arg820Trp）与银屑病存在关联（P值=2.1×10^-6）。在两个规模最大的银屑病队列中，当对人类白细胞抗原-Cw*0602（HLA-Cw*0602，PSORS1）进行校正后，rs11652075与银屑病的关联证据进一步增强。本研究有助于加深我们对银屑病遗传基础的理解，并阐明了在常见疾病中识别致病变异所面临的挑战。总体实验设计：将角质形成细胞（keratinocytes）转染野生型CARD14或16种CARD14突变体（共17个样本），收集细胞并提取RNA，以分析相较于野生型CARD14，这些突变所产生的影响。本实验未设置生物学重复。