Application of digital PCR with chip-in-a-tube format to analyze Adenomatous polyposis coli (APC) somatic mosaicism

Background: Over the past decade, digital PCR (dPCR) technology has significantly improved, and its application in clinical diagnostics is rapidly advancing. The Clarity (TM) dPCR platform, which employs the chip-in-a-tube format to broaden its range of applications, has been used to determine gene copy number. However, detection of mutations in human samples, the most demanding task in clinical practice, has not yet been reported using this platform. Methods: The Clarity (TM) dPCR platform was used to detect somatic Adenomatous polyposis coli mosaicism c.834 + 2 T > C, which had been identified using next-generation sequencing (NGS) technology in a patient with sporadic familial adenomatous polyposis. In addition, we were able to determine the size of the dPCR product. Results: The mutation rate in the peripheral blood of the patient calculated using the dPCR platform was 13.2%. This was similar to that determined using NGS (12.7%). In contrast, in healthy donors, the mutation rate was < 0.1%. Furthermore, it was confirmed that the dPCR product size was consistent with its theoretical value. Conclusion: Our results show that the dPCR platform with the chip-in-a-tube format is suitable for the analysis of mosaicism and enables the validation of the dPCR product size.