Park Sunggyun, Lee Hyeonah, Shin Saeam, Lee Seung-Tae, Lee Kyung-A, Choi Jong Rak
Department of Laboratory Medicine, Keimyung University School of Medicine, Daegu, Republic of Korea.
Brain Korea 21 PLUS Project for Medical Science, Yonsei University, Seoul, Republic of Korea.
Clin Chim Acta. 2020 Nov;510:787-789. doi: 10.1016/j.cca.2020.09.024. Epub 2020 Sep 19.
Spinal muscular atrophy (SMA) is a progressive motor neuron disease caused by homozygote loss of exon 7 on the survival motor neuron 1 (SMN1) gene. The severity of the SMA phenotype is influenced by copies of SMN2, a gene that is highly homologous with SMN1.
We validated analytical performance of droplet digital polymerase chain reaction (ddPCR) for detection of copy number variation of SMN1 and SMN2 genes for diagnosis of SMA using clinical samples. For accuracy performance evaluation, ddPCR results were compared with those of multiplex ligation-dependent probe amplification (MLPA) as a reference standard. Copy numbers of SMN1/SMN2 exon 7 from 200 clinical samples were concordant between ddPCR and MLPA.
For all samples, the copy number of SMN1/SMN2 exon 7 was concordant between MLPA and ddPCR. The ddPCR also showed acceptable degrees of repeatability and total imprecision.
Therefore, ddPCR is expected to be useful for SMA diagnosis and to predict phenotypic severity of SMA patients by determining the copy number of SMN2 in clinical laboratories.
脊髓性肌萎缩症（SMA）是一种由生存运动神经元1（SMN1）基因第7外显子纯合缺失引起的进行性运动神经元疾病。SMA表型的严重程度受SMN2基因拷贝数的影响，SMN2基因与SMN1基因高度同源。
我们使用临床样本验证了液滴数字聚合酶链反应（ddPCR）检测SMN1和SMN2基因拷贝数变异以诊断SMA的分析性能。为了评估准确性，将ddPCR结果与作为参考标准的多重连接依赖探针扩增（MLPA）结果进行比较。来自200份临床样本的SMN1/SMN2第7外显子的拷贝数在ddPCR和MLPA之间具有一致性。
对于所有样本，MLPA和ddPCR检测的SMN1/SMN2第7外显子的拷贝数具有一致性。ddPCR还显示出可接受的重复性和总不精密度。
因此，预计ddPCR在临床实验室中通过测定SMN2的拷贝数，对SMA诊断及预测SMA患者的表型严重程度有用。
