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Size-based molecular diagnostics using plasma DNA for noninvasive prenatal testing. | LitMetric

Size-based molecular diagnostics using plasma DNA for noninvasive prenatal testing.

Proc Natl Acad Sci U S A

Centre for Research into Circulating Fetal Nucleic Acids, Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Shatin, NT, Hong Kong SAR, China;Department of Chemical Pathology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, NT, Hong Kong SAR, China;

Published: June 2014

AI Article Synopsis

  • The study investigates a novel method of noninvasive prenatal testing that analyzes the size of DNA fragments in maternal plasma to distinguish fetal DNA from maternal DNA, leveraging the fact that fetal DNA is typically shorter.
  • By using advanced techniques like massively parallel sequencing and microchip-based capillary electrophoresis, researchers can determine the fetal DNA fraction in maternal plasma, which significantly impacts the test's accuracy.
  • The study successfully detects chromosomal abnormalities such as trisomy 21 and 18 with high accuracy rates (100% sensitivity and specificity), suggesting that size-based approaches could also be useful in other fields like cancer diagnostics and organ transplant monitoring.

Article Abstract

Noninvasive prenatal testing using fetal DNA in maternal plasma is an actively researched area. The current generation of tests using massively parallel sequencing is based on counting plasma DNA sequences originating from different genomic regions. In this study, we explored a different approach that is based on the use of DNA fragment size as a diagnostic parameter. This approach is dependent on the fact that circulating fetal DNA molecules are generally shorter than the corresponding maternal DNA molecules. First, we performed plasma DNA size analysis using paired-end massively parallel sequencing and microchip-based capillary electrophoresis. We demonstrated that the fetal DNA fraction in maternal plasma could be deduced from the overall size distribution of maternal plasma DNA. The fetal DNA fraction is a critical parameter affecting the accuracy of noninvasive prenatal testing using maternal plasma DNA. Second, we showed that fetal chromosomal aneuploidy could be detected by observing an aberrant proportion of short fragments from an aneuploid chromosome in the paired-end sequencing data. Using this approach, we detected fetal trisomy 21 and trisomy 18 with 100% sensitivity (T21: 36/36; T18: 27/27) and 100% specificity (non-T21: 88/88; non-T18: 97/97). For trisomy 13, the sensitivity and specificity were 95.2% (20/21) and 99% (102/103), respectively. For monosomy X, the sensitivity and specificity were both 100% (10/10 and 8/8). Thus, this study establishes the principle of size-based molecular diagnostics using plasma DNA. This approach has potential applications beyond noninvasive prenatal testing to areas such as oncology and transplantation monitoring.

Download full-text PDF

Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4060699PMC
http://dx.doi.org/10.1073/pnas.1406103111DOI Listing

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