CARD8基因新发P367L失功能突变患者自身炎症性疾病的临床及免疫学特征

The clinical manifestations and immune features of a patient with novel CARD8 loss-of-function mutation leading to autoinflammatory diseases

目的报道1例CARD8基因新发突变导致自身炎症性疾病患儿及其家系的临床特征、致病性鉴定与免疫致病机制。方法收集并分析1例CARD8基因突变患儿的突变位点以及临床资料,随访患儿治疗及预后;采用全外显子测序发现可疑致病基因并利用Sanger测序验证家系突变位点;利用体外实验进行致病性验证及免疫学分析。结果先证者为1名男性患儿,主要临床表现为极早发的食物蛋白过敏性肠炎、特应性皮炎及反复发作的上消化道出血。实验室检查提示血清IgE升高。全外显子测序发现CARD8基因新发杂合突变c.1100C>T(p.P367L),且该突变位点经Sanger测序验证证实来源于其父亲。该突变致病性不明确,且既往未见报道。实验室检查提示患儿血浆中多种促炎细胞因子水平显著升高。患儿原代外周血单个核细胞(PBMCs)及转染相同突变质粒的293T细胞CARD8蛋白表达均显著降低。患儿PBMCs中NLRP3炎性小体过度激活,而NF-κB通路无异常。以上研究均提示患儿的CARD8基因p.P367L突变为失功能性致病突变。结论本文报道全球第2例,中国第1例CARD8基因杂合突变患儿及家系,并明确CRAD8基因c.1100C>T的突变致病性。该CARD8基因失功能突变可导致NLRP3炎性小体的过度激活而诱发患儿发生以消化道症状起病的自身炎症性疾病。

CARD8 is known to negatively regulate the activation of the NLRP3 inflammasome,a crucial element of the innate immune system.Our study presents an in-depth analysis of the clinical manifestations and immunological traits of a patient carrying a novel mutation in the CARD8 gene.This patient presented a unique clinical pattern marked by early-onset recurrent food protein-induced enteritis,atopic dermatitis,and repeated episodes of upper gastrointestinal bleeding.Laboratory analysis revealed a notable increase in serum IgE levels with lymphocyte counts within normal range.The patient underwent screening through capture next-generation sequencing(CNGS)and Sanger sequencing,identifying a novel heterozygous mutation in the CARD8 gene(c.1100C>T;p.P367L)inherited from his father.We assessed this mutation using the combined annotation-dependent depletion(CADD)score,which returned high values.We also confirmed the pathogenic of this mutation by observing reduced protein expression,increased cytokine activity,and heightened activation of the NLRP3 inflammasome in the patient compared to healthy controls.In conclusion,our research documents the first case of CARD8 mutation in China and the second globally.This study contributes to a broader understanding of clinical spectrum in the autoinflammatory disease and may offer new insights into the underlying pathogenesis of CARD8 mutation.