Presymptomatic Diagnosis of Spinal Muscular Atrophy Through Newborn Screening
Journal
Journal of Pediatrics
Journal Volume
190
Pages
124-1290
Date Issued
2017
Author(s)
Chiang S.-C.
Lin C.-J.
Hsieh W.-S.
Jong Y.-J.
Abstract
Objective To demonstrate the feasibility of presymptomatic diagnosis of spinal muscular atrophy (SMA) through newborn screening (NBS). Study design We performed a screening trial to assess all newborns who underwent routine newborn metabolic screening at the National Taiwan University Hospital newborn screening center between November 2014 and September 2016. A real-time polymerase chain reaction (RT-PCR) genotyping assay for the SMN1/SMN2 intron 7 c.888+100A/G polymorphism was performed to detect homozygous SMN1 deletion using dried blood spot (DBS) samples. Then the exon 7 c.840C>T mutation and SMN2 copy number were determined by both droplet digital PCR (ddPCR) using the original screening DBS and multiplex ligation-dependent probe amplification (MLPA) using a whole blood sample. Results Of the 120 267 newborns, 15 tested positive according to the RT-PCR assay. The DBS ddPCR assay excluded 8 false-positives, and the other 7 patients were confirmed by the MLPA assay. Inclusion of the second-tier DBS ddPCR screening assay resulted in a positive prediction value of 100%. The incidence of SMA was 1 in 17 181 (95% CI, 1 in 8323 to 1 in 35 468). Two of the 3 patients with 2 copies of SMN2 and all 4 patients with 3 or 4 copies of SMN2 were asymptomatic at the time of diagnosis. Five of the 8 false-positives were caused by intragenic recombination between SMN1 and SMN2. Conclusion Newborn screening can detect patients affected by SMA before symptom onset and enable early therapeutic intervention. A combination of a RT-PCR and a second-tier ddPCR can accurately diagnose SMA from DBS samples with no false-positives. Trial registration ClinicalTrials.gov NCT02123186. ? 2017 Elsevier Inc.
SDGs
Other Subjects
DNA fragment; survival motor neuron protein 1; survival motor neuron protein 2; SMN1 protein, human; SMN2 protein, human; survival motor neuron protein 1; survival motor neuron protein 2; Article; asymptomatic disease; blood sampling; diagnostic accuracy; dried blood spot testing; droplet digital polymerase chain reaction; false positive result; female; follow up; gene amplification; gene mutation; genetic counseling; genetic variation; health program; human; incidence; intron; major clinical study; male; multiplex ligation dependent probe amplification; newborn; newborn screening; point mutation; prediction; priority journal; prospective study; real time polymerase chain reaction; reverse transcription polymerase chain reaction; Sanger sequencing; spinal muscular atrophy; clinical trial; early diagnosis; genetics; infant; newborn screening; pilot study; procedures; spinal muscular atrophy; Taiwan; Early Diagnosis; Female; Humans; Infant; Infant, Newborn; Male; Muscular Atrophy, Spinal; Neonatal Screening; Pilot Projects; Real-Time Polymerase Chain Reaction; Survival of Motor Neuron 1 Protein; Survival of Motor Neuron 2 Protein; Taiwan
Publisher
Mosby Inc.
Type
journal article