Prenatal diagnosis of genetic diseases directly using paper-dried cord blood as the starting material for PCR.

A rapid and low-cost method of diagnosis is becoming important for detecting fetal inherited diseases, including single-gene disorders and chromosomal abnormalities. Here, we demonstrated an innovation that use paper-dried cord blood (PCB) as the starting material for PCR and whole genome amplification without any DNA extraction step at a very low cost. A novel PCR buffer named "DDB buffer" containing ammonium sulfate and glycerol were used instead of the conventional 10× PCR buffer. The amplicons were directly analyzed through microchip electrophoresis and whole genome sequencing. Inhibitory substances in filter paper were effectively inactivated using DDB buffer. Direct PCR amplification of DNA fragments ranging from 100 to 900 bp using filter paper spotted with 0.5 to 5 μL of cord blood and various anticoagulants was successful. We were able to determine fetal single-gene disorders and chromosomal diseases in all 46 chromosomes using PCB samples successfully. Compared with prenatal diagnosis using purified DNA, the proposed method is simple, fast, less prone to cross-contamination at minimal cost. Researchers and clinical and healthcare workers may employ this method for genetic diagnosis using cord blood samples with minimum laboratory resources. This method is very promising for a variety of genetic diagnosis applications in underserved communities at the point of need in developing areas. Graphical abstract.