Department of Pediatrics, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
Department of Immunology-CDB, Hospital Clínic-IDIBAPS, Barcelona, Spain.
Ann Rheum Dis. 2015 Mar;74(3):603-10. doi: 10.1136/annrheumdis-2013-204361. Epub 2013 Dec 10.
: Familial cold autoinflammatory syndrome, Muckle-Wells syndrome (MWS), and chronic, infantile, neurological, cutaneous and articular (CINCA) syndrome are dominantly inherited autoinflammatory diseases associated to gain-of-function NLRP3 mutations and included in the cryopyrin-associated periodic syndromes (CAPS). A variable degree of somatic NLRP3 mosaicism has been detected in ≈35% of patients with CINCA. However, no data are currently available regarding the relevance of this mechanism in other CAPS phenotypes.
To evaluate somatic NLRP3 mosaicism as the disease-causing mechanism in patients with clinical CAPS phenotypes other than CINCA and NLRP3 mutation-negative.
NLRP3 analyses were performed by Sanger sequencing and by massively parallel sequencing. Apoptosis-associated Speck-like protein containing a CARD (ASC)-dependent nuclear factor kappa-light chain-enhancer of activated B cells (NF-κB) activation and transfection-induced THP-1 cell death assays determined the functional consequences of the detected variants.
A variable degree (5.5-34.9%) of somatic NLRP3 mosaicism was detected in 12.5% of enrolled patients, all of them with a MWS phenotype. Six different missense variants, three novel (p.D303A, p.K355T and p.L411F), were identified. Bioinformatics and functional analyses confirmed that they were disease-causing, gain-of-function NLRP3 mutations. All patients treated with anti-interleukin1 drugs showed long-lasting positive responses.
We herein show somatic NLRP3 mosaicism underlying MWS, probably representing a shared genetic mechanism in CAPS not restricted to CINCA syndrome. The data here described allowed definitive diagnoses of these patients, which had serious implications for gaining access to anti-interleukin 1 treatments under legal indication and for genetic counselling. The detection of somatic mosaicism is difficult when using conventional methods. Potential candidates should benefit from the use of modern genetic tools.
家族性冷自身炎症综合征、Muckle-Wells 综合征（MWS）和慢性婴儿神经皮肤关节综合征（CINCA）是显性遗传性自身炎症性疾病，与功能获得性 NLRP3 突变相关，并被纳入 Cryopyrin 相关周期性综合征（CAPS）。在约 35%的 CINCA 患者中检测到 NLRP3 体细胞镶嵌现象，但目前尚无关于该机制在其他 CAPS 表型中的相关性的数据。
评估体细胞 NLRP3 镶嵌现象作为除 CINCA 和 NLRP3 突变阴性以外的具有临床 CAPS 表型患者的致病机制。
通过 Sanger 测序和大规模平行测序进行 NLRP3 分析。凋亡相关斑点样蛋白包含一个 CARD（ASC）依赖性核因子κB 轻链增强子的激活物（NF-κB）激活和转染诱导的 THP-1 细胞死亡测定确定了所检测变异的功能后果。
在纳入的患者中，有 12.5%的患者存在不同程度的（5.5%-34.9%）体细胞 NLRP3 镶嵌现象，所有患者均表现为 MWS 表型。共鉴定出 6 种不同的错义变异，其中 3 种为新发现的（p.D303A、p.K355T 和 p.L411F）。生物信息学和功能分析证实它们是致病的、功能获得性 NLRP3 突变。所有接受抗白细胞介素 1 药物治疗的患者均表现出持久的阳性反应。
我们在此证明了 MWS 中存在体细胞 NLRP3 镶嵌现象，这可能代表了 CAPS 中的一种共同遗传机制，不仅限于 CINCA 综合征。这些数据为这些患者做出了明确的诊断，这对获得合法适应症下的抗白细胞介素 1 治疗和遗传咨询产生了严重影响。当使用传统方法时，体细胞镶嵌现象的检测较为困难。潜在的候选者应受益于现代遗传工具的使用。
