文献_Genotyping fetal paternally inherited SNPs by MALDI-TOF MS using cell-free fetal DNA in maternal plasma influence of size fractionation.pdf

Electrophoresis 2006, 27, 3889–3896 3889 Ying Li1 Research Article Friedel Wenzel2 Wolfgang Holzgreve1 Sinuhe Hahn1 Genotyping fetal paternally inherited SNPs by 1University Women’s Hospital, MALDI-TOF MS using cell-free fetal DNA in Department of Research, maternal plasma: Influence of size Basel, Switzerland 2Medical Genetics, fractionation Department of Research, Basel, Switzerland The determination of fetal point mutations from fetal cell-free DNA (cf-DNA) in maternal Received February 16, 2006 plasma is technically challenging due to the preponderance of maternal sequences. It Revised May 16, 2006 has recently been shown that fetal cf-DNA sequences are smaller than maternal ones Accepted June 23, 2006 and that the selection of small cf-DNA fragments by size fractionation by agarose gel electrophoresis leads to the enrichment of fetal cf-DNA sequences, thereby permitting the detection of otherwise masked fetal point mutations. In a separate development, the use of MALDI-TOF MS has also been shown to facilitate the detection of fetal point mutations from cf-DNA in maternal plasma. In this study, a combination of these approaches was examined. cf-DNA was extracted from 18 maternal plasma samples, 10 taken at term and 8 obtained early in the second trimester. A total of 41 SNP loci were examined in size-fractionated and total cf-DNA using either a conventional ho-