Genetic screening of spinal muscular atrophy using a real-time modified COP-PCR technique with dried blood-spot DNA

Publication date: Available online 15 May 2017
Source:Brain and Development
Author(s): Mawaddah Ar Rochmah, Nur Imma Fatimah Harahap, Emma Tabe Eko Niba, Kenta Nakanishi, Hiroyuki Awano, Ichiro Morioka, Kazumoto Iijima, Toshio Saito, Kayoko Saito, Poh San Lai, Yasuhiro Takeshima, Atsuko Takeuchi, Yoshihiro Bouike, Maya Okamoto, Hisahide Nishio, Masakazu Shinohara
BackgroundSpinal muscular atrophy (SMA) is a common neuromuscular disorder caused by mutations in SMN1. More than 95% of SMA patients carry homozygous SMN1 deletion. SMA is the leading genetic cause of infant death, and has been considered an incurable disease. However, a recent clinical trial with an antisense oligonucleotide drug has shown encouraging clinical efficacy. Thus, early and accurate detection of SMN1 deletion may improve prognosis of many infantile SMA patients.MethodsA total of 88 DNA samples (37 SMA patients, 12 carriers and 39 controls) from dried blood spots (DBS) on filter paper were analyzed. All participants had previously been screened for SMN genes by PCR restriction fragment length polymorphism (PCR-RFLP) using DNA extracted from freshly collected blood. DNA was extracted from DBS that had been stored at room temperature (20–25°C) for 1week to 5years. To ensure sufficient quality and quantity of DNA samples, target sequences were pre-amplified by conventional PCR. Real-time modified competitive oligonucleotide priming-PCR (mCOP-PCR) with the pre-amplified PCR products was performed for the gene-specific amplification of SMN1 and SMN2 exon 7.ResultsCompared with PCR-RFLP using DNA from freshly collected blood, results from real-time mCOP-PCR using DBS-DNA for detection of SMN1 exon 7 deletion showed a sensitivity of 1.00 (CI [0.87, 1.00])] and specificity of 1.00 (CI [0.90, 1.00]), respectively.ConclusionWe combined DNA extraction from DBS on filter paper, pre-amplification of target DNA, and real-time mCOP-PCR to specifically detect SMN1 and SMN2 genes, thereby establishing a rapid, accurate, and high-throughput system for detecting SMN1-deletion with practical applications for newborn screening.



http://ift.tt/2qofyCu