A novel method for noninvasive diagnosis of monogenic diseases from circulating fetal cells

Objective To establish a method for noninvasive fetal cell isolation from maternal blood and prenatal testing of monogenic diseases by a combination of direct sequencing and targeted NGS-based SNP haplotyping from single fetal cells. Method Peripheral blood of pregnant women in two families (congenital deafness and ichthyosis) was collected. After density-based separation and immunostaining with multiple biomarkers, candidate fetal cells were identified by high-throughput imagine analysis and picked up by automation. Individual fetal cells were subjected to STR-genotyping to identify their origin. Pathogenic mutations were identified by direct Sanger sequencing, and a combination of targeted NGS and SNP haplotyping using a custom panel. All the results were compared with amniotic fluid DNA. Results Fetal trophoblasts were successfully harvested from maternal blood. STR-genotyping confirmed the fetal origin. Direct sequencing of pathogenic genetic mutations in fetal cells showed consistent results with amniotic fluid samples. For congenital deafness family, NGS-based SNP haplotyping also correctly identified the fetal haplotype. This single cell haplotyping method can be used to diagnose various genetic diseases. Conclusion We have established a method for noninvasive prenatal testing of monogenic diseases from circulating trophoblast cells. This cell-based NIPT can be further applied to the prenatal diagnosis of various monogenic diseases.

Automated summary

A method for noninvasive prenatal testing of monogenic diseases by isolating fetal cells from maternal blood and using direct sequencing and targeted NGS-based SNP haplotyping was successfully established. The fetal origin of the cells and the identification of pathogenic mutations were confirmed through genetic analysis, showing consistent results with amniotic fluid samples. This single cell haplotyping method can be used for diagnosing various genetic diseases.