疑似遗传代谢病的高危新生儿行质谱检测与高通量测序检测诊断准确性研究

目的比较质谱检测与高通量测序(NGS)筛查疑似遗传代谢病(IMD)的高危新生儿的诊断效能。方法纳入2016年8月至2018年6月复旦大学附属儿科医院(我院)临床表现疑似IMD的高危新生儿,患儿监护人知情同意患儿参加质谱检测和NGS筛查IMD,以NGS检测(包含2 742个已知致病基因)为金标准,以质谱检测(包含20种氨基酸代谢病、12种脂肪酸代谢病和19种有机酸代谢病)为待测标准,随访至6月龄结局。结果纳入2 000例疑似IMD的高危新生儿,NGS诊断IMD 33例(1.7%),涉及21种IMD;质谱检测结果异常154例(7.7%),提示IMD可能26例、继发性改变可能128例。以NGS检测结果为金标准,质谱检测提示IMD可能+提示继发性改变可能为待测标准1,质谱检测的敏感度93.9%(95%CI:79.8%～99.3%),特异度93.8%(95%CI:92.6%～94.8%)。质谱检测提示IMD可能(待测标准2)与NGS相符13例;质谱检测提示某一类或某几种IMD可能11例,NGS均明确并细化了疾病类型;质谱检测提示IMD可能,但与NGS检测结果不一致2例;质谱检测提示继发性改变可能5例,NGS检测为致病/可疑致病变异,明确并细化了疾病类型。待测标准1中,质谱结果正常的1 846例中,NGS发现2例IMD。NGS诊断的IMD有5例不包含在本文质谱检测的病种中。NGS诊断IMD 33例,有机酸代谢异常8种15例、氨基酸代谢异常7种9例、脂肪酸氧化代谢异常3种6例、其他类型IMD共3例;可疑遗传代谢病家庭史12例;以6月龄为随访终点统计,13例IMD患儿家属放弃治疗死亡,2例抢救无效死亡; 18例IMD患儿临床诊疗方案得以明确,7例因获得及时有效的治疗目前生长发育良好,11例有不同程度的发育落后,主要以精神运动发育迟缓为主,部分伴有听力损害。结论质谱检测+NGS检测较单纯质谱检测可以更加快速且全面确诊临床表现疑似IMD的高危新生儿,尽早实施个体化治疗,改善患儿预后。

The diagnosis of inherited metabolic disorders in high risk neonates: mass spectrometry and high throughput sequencing

Objective To compare the diagnostic accuracy of mass spectrometry and high throughput sequencing in screening neonates at high risk of suspected inherited metabolic disorders (IMD). Methods Neonates with suspected IMD were referred to mass spectrometry and next generation sequencing (NGS) with the consent of their guardians from August 2016 to June 2018. Taking NGS (containing 2 742 known pathogenic genes) as the gold standard, the diagnostic value of mass spectrometry (screening diseases including 20 amino acid metabolic diseases, 12 fatty acid metabolic diseases and 19 organic acid diseases) for IMD was discussed. Results Thirty-three of 2 000 neonates with suspected IMD were diagnosed by NGS, including 8 kinds of abnormal organic acid metabolism(15 cases), 7 kinds of abnormal amino acid metabolism(9 cases), 3 kinds of abnormal fatty acid oxidation metabolism(6 cases) and 3 cases of other types of IMD. In these patients, mass spectrometry indicated that there were 128 cases of secondary changes and 26 cases of IMD. When both IMD and secondary changes were considered positive according to the results of mass spectrometry, the sensitivity and specificity of mass spectrometry were 93.9% (95%CI: 79.8%-99.3%) and 93.8% (95%CI:92.6%-94.8%) respectively. In special types of IMD indicated by mass spectrometry, there were 13 cases consistent with NGS, but 2 cases were inconsistent with NGS. Indicated by mass spectrometry, NGS detected pathogenic/likely pathogenic variants of related IMD in 11 cases with several alternatives of IMD, 5 cases with secondary changes and 2 cases with normal results. Five IMDs identified by NGS were not included in the disease spectrum of mass spectrometry in our study. Among the patients with IMD, 12 had family history of suspected IMD. In the 6th month after birth, 13 cases with IMD died of abandoned treatments and 2 cases died of invalid rescue. NGS established therapeutic schemes for 18 infants with IMD. In these patients, 7 developed well and 11 had developmental delay, mainly psychomotor retardation, some of which had hearing impairment. Conclusion Compared with mass spectrometry, the combination of mass spectrometry and NGS can diagnose neonates of suspected IMD more quickly so as to implement individualized treatment as early as possible and improve the prognosis of patients.