Accuracy and feasibility of non-invasive prenatal testing for FGFR3-related skeletal dysplasia by next-generation sequencing

Objective To explore the test accuracy and feasibility of non-invasive prenatal testing for FGFR3- related skeletal dysplasia based on next-generation sequencing (NGS). Method Fragmented fetal genome DNA (gDNA) of achondroplasia (n=4) or thanatophoric dysplasia typeⅠ(n=2) were diluted by corresponding post-delivery maternal cell-free DNA into different concentrations including 10%, 6%, 3%, 1% and 0.5% (n=30). Cell-free DNA collected from pregnant women (n=13) whose fetuses were confirmed free of FGFR3 mutation by Sanger sequencing served as negative control . Then NGS was carried out to detect he fetal mutant allele in these samples. Sensitivity, specificity, positive predictive value, negative predictive value were calculated o evaluate the test performance. Results When the fetal gDNA concentrations were 10%, 6%, 3%, 1% and 0.5%，the detection ates were 6/6, 6/6, 6/6, 3/6 and 1/6, respectively. NGS had a sensitivity of 100%(95% CI: 81.5%-99.9%)when the fetal genome DNA concentration was equal to or more than 3%. There was no positive result in the negative controls and the specificity of NGS was 100%(95% CI: 75.3%-100%). The positive predictive value and negative predictive value were 100%(95% CI: 81.5%-100%) and 100%(95% CI: 75.3%-100%), respectively. Conclusion NGS has a high accuracy in detecting FGFR3 mutation when the concentration of fetal gDNA is equal to or more than 3% , highlighting its promising value in developing non-invasive prenatal test or monogenic disorders, especially for the denovo and paternal inherited diseases.