SMN1 gene deletion analysis using mid-trimester amniotic fluid cells by real-time PCR / 中华检验医学杂志

ABSTRACT

Objectives To investigate the prenatal diagnosis method of spinal muscular atrophy with amniotic fluid sample.Methods Totally 1 064 amniotic fluid samples from mid-trimester pregnant women were enrolled during January 2015 and January 2016 in 4 hospitals.Genetic analysis was performed for detecting potential contamination of maternal tissue by a genetic technique based on short tandem repeat ( STR) markers.Deletion of SMN1 gene was detected in 1 062 uncontaminated amniotic fluid samples by real-time PCR and multiplex ligation-dependent probe amplification ( MLPA) respectively.Results Two contaminated amniotic fluid samples were detected within 1 064 mid-trimester pregnant women by STR genotyping.The other 1 062 uncontaminated amniotic fluid samples were tested by real-time PCR.There were 37 samples with heterozygous deletion of Exon 7 of SMN1 gene ( 3.67%) , 34 samples with heterozygous deletion of Exon 8 of SMN1 gene (3.2%) and two samples with homozygous deletion of Exon 7 and Exon8 of SMN1 gene ( 0.19%) respectively , while other samples observed with no deletion of Exon 7 and Exon8 in SMN1 gene.Totally 41 samples with heterozygous or homozygous deletion of SMN 1 gene and 55 samples with undetected deletion of SMN 1 gene were confirmed by MLPA and the results showed 100%consistence with that of real-time PCR.Conclusions Both real-time PCR and MLPA are suitable for detecting the deletion of SMN 1 gene with amniotic fluid sample . Real-time PCR exhibits less sample requirement and time compared with MLPA .