Abstract
ObjectiveTo develop a technique for non‐invasive prenatal diagnosis of spinal muscular atrophy and validate its performance.Study DesignPregnant women with 1 copy of SMN1 and male fetuses were enrolled. Seventeen women were included in test set A, and 10 of them were selected into test set B randomly and blinded. The two sets were tested independently by two different researchers blinded to fetal genotypes. Fetal DNA fractions were calculated based on the relative proportion of mapped chromosome Y sequencing reads. An algorithm was developed to decide fetal SMN1 copy numbers.ResultsThe concordance rate with the results of MLPA testing of amniocyte DNA was 94.12% in test set A and 90% in set B. For all tests with a classifiable result, the percent of agreement with the results of MLPA testing of amniocyte DNA was up to 100% (25/25).ConclusionWe have developed a direct, rapid, and low‐cost technique, which has a potential to be utilized for first‐trimester non‐invasive prenatal diagnosis and screening for spinal muscular atrophy with considerable reliability and feasibility.
Highlights
Spinal muscular atrophy (SMA) is one of the most common autoso‐ mal recessive diseases causing infant mortality, with an incidence around 1 in 10 000 births.[1]
Survival motor neuron 2 (SMN2) gene is located in the 5q13 region, the coding sequence of which differs from SMN1 only by the 6th nucleotide of exon 7, where a C‐to‐T transition leads to the alternatively spliced isoform translating the non‐functional SMN△7 protein.[4,5]
Results of TaqMan quantitative real‐time PCR conducted on genomic DNA samples with various SMN1/SMN2 copy numbers were com‐ pletely in accordance with the multiplex ligation‐dependent probe amplification (MLPA) results
Summary
Spinal muscular atrophy (SMA) is one of the most common autoso‐ mal recessive diseases causing infant mortality, with an incidence around 1 in 10 000 births.[1]. For NIPD of SMA, a technique by targeted sequencing of cfDNA in maternal plasma and relative haplotype dosage (RHDO) analysis has been. Utilizing digital PCR, the feasibility of non‐invasive prena‐ tal diagnosis (NIPD) for fetal monogenic disorders has been proved in several studies analyzing cfDNA.[12,13,14,15,16] In particular, for maternally inherited single nucleotide mutations, the relative mutation dosage (RMD) analysis based on the sequential probability ratio test (SPRT) has enabled detection of a slight increase in the load of the mutant allele in the maternal plasma of heterozygous carriers.[17] Digital PCR provides an ideal platform for the development of a haplotype‐free test strategy for SMA‐NIPD. We present a novel technique that directly analyses SMN1 gene dosage using droplet digital PCR, as well as the results of performance validation
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
