儿童临床诊断不明呼吸系统疾病97例基因二代测序结果分析

Analysis using next generation sequencing in 97 children with unknown respiratory diseases

目的探讨基因二代测序在儿童呼吸系统疑难疾病中的诊断应用。方法回顾性分析2016—2021年采用二代测序对以呼吸系统症状为主要表现的疑难疾病的诊断情况,总结患儿的临床特征及基因二代测序结果。结果进行基因二代测序的患儿共97例,均以呼吸系统症状为首发或主要表现,中位年龄1.9(7.6)岁,男57例、女40例。确诊单基因病31例(诊断率32.0%),中位年龄4.0(7.6)岁;主要表现为慢性湿性咳嗽,部分患儿进展到后期有不同程度的营养不良、杵状指。其中原发性纤毛运动障碍20例,18例为复合杂合变异(HYDIN 7例、CCNO 3例、CCDC402例、DNAH12例、DNAAF31例、DNAI21例、DNAH111例、RSPH4A 1例);1例为DNAI2基因纯合变异;1例存在X连锁PIH1D3基因半合子缺失。囊性纤维化4例,其中3例为CFTR基因复合杂合变异,1例为CFTR基因c.4056G>C纯合变异。肺表面活性物质代谢障碍3例,均为SFTPC基因杂合变异。原发性免疫缺陷病2例,分别为PIK3CD基因变异致PI3Kδ过度活化综合征1例、CXCR4基因变异致WHIM综合征1例。神经肌肉疾病2例,为MTM1基因变异致中央核肌病1例、SMN1基因纯合缺失致进行性脊肌萎缩症1例。66例基因检测阴性患儿以反复呼吸道感染和慢性咳嗽表现为主,伴或不伴支气管扩张;部分患儿表现为不明原因气促、呼吸窘迫,伴或不伴肺部广泛间质改变。结论以呼吸系统症状为首发或主要表现的儿童单基因病具有高度的临床和遗传异质性,基因二代测序的应用给诊治带来了新思路,扩展对疾病谱的认识。

Objective To explore the application of next generation sequencing(NGS)in the diagnosis of intractable respiratory diseases in children.Methods A retrospective analysis was performed on the diagnosis of intractable diseases with respiratory symptoms as the main manifestations in the respiratory center of our hospital from 2016 to 2021,and the clinical effectiveness of NGS was further evaluated.Results A total of 97 children underwent NGS testing,all of which had respiratory symptoms as the first or main manifestation.The median age was 1 year and 11 months,and the male to female ratio was 1.4:1(57/40).Using NGS testing,31 cases of monogenic disease were diagnosed at a median age of 4 years,and the diagnosis rate was about 32.0%.Among them were 20 cases of primary ciliary dyskinesia.The results of gene detection showed that 18 cases had compound heterozygous mutation,including seven cases of HYDIN,three cases of CCNO,two cases of CCDC40,two cases of DNAH1,one case each of DNAAF3,DNAI2,DNAH11,RSPH4A,homozygous mutation at DNAI2 gene and of hemizygous deletion of PIH1D3 gene.There were four cases of cystic fibrosis,among them three cases had compound heterozygous mutation in CFTR gene and one case had a homozygous mutation of c.4056G>C in CFTR gene.There were three cases of pulmonary surfactant metabolic disorder,all of them had heterozygous mutations in SFTPC gene.There were two cases of primary immunodeficiency disease,including one case of PI3Kδoveractivation syndrome caused by PIK3CD gene mutation and one case of WHIM syndrome caused by CXCR4 gene mutation.There were two cases of neuromuscular diseases including one case of centronuclear myopathy caused by MTM1 gene mutation and one case of progressive spinal muscular atrophy caused by homozygous deletion of SMN1 gene.The clinical manifestations of 31 children with positive gene test included chronic wet cough(n=27),shortness of breath(n=10),recurrent nasal congestion(n=18),runny nose(n=18),external ear pus(n=6),malnutrition(n=11),visceral transposition(n=3)and clubbing finger(n=5).Chest CT revealed bronchiectasis in 14 cases,atelectasis in eight cases and pulmonary interstitial changes in eight cases.The 66 children with negative genetic test were mainly manifested by recurrent respiratory tract infection and chronic cough,with or without bronchiectasis,some children presented with unexplained shortness of breath and respiratory distress,with or without extensive interstitial changes in the lungs.Conclusion Monogenic disease in children with respiratory symptoms as the first or main manifestation has a high degree of clinical and genetic heterogeneity.The application of the next generation sequencing brings new ideas to its diagnosis and treatment and expands people’s understanding of the diseasespectrum.