1. Restriction Enzyme–Mediated Enhanced Detection of Circulating Cell-Free Fetal DNA in Maternal Plasma 
John A. Tynan, Payam Mahboubi, Lesley L. Cagasan, Dirk van den Boom, Mathias Ehrich, Paul Oeth 
The Journal of Molecular Diagnostics 
Volume 13, Issue 4, Pages (July 2011)
DOI: /j.jmoldx
Copyright © 2011 American Society for Investigative Pathology and the Association for Molecular Pathology Terms and Conditions

2. Figure 1
Schematic showing the work flow of the FI assay. Blood samples are fractionated into maternal PBMC–buffy coat and plasma. DNA is isolated from both fractions of the maternal blood. Maternal buffy coat DNA is genotyped for all 92 SNPs without RE digestion. Maternal plasma is digested with RE in PCR cocktail before thermal cycling and subsequently genotyped for all 92 SNPs. Maternal buffy coat genotype is determined; when a maternal buffy coat DNA SNP is homozygous for the digestible allele, the nondigestible allele peak area ratios from maternal plasma and maternal buffy coat are compared. SAP/PE indicates shrimp alkaline phosphatase treatment and primer extension; MALDI, matrix-assisted laser desorption ionization.
The Journal of Molecular Diagnostics  , DOI: ( /j.jmoldx )
Copyright © 2011 American Society for Investigative Pathology and the Association for Molecular Pathology Terms and Conditions

3. Figure 2
Feasibility of RE-mediated selective SNP allele detection at the LFC. The tabular column at the left of the spectra indicates the percentage heterozygous DNA added to a DNA homozygous for the A allele of rs A total of 200 copies of heterozygous DNA were assayed in each instance. Left: The five spectra in the undigested group demonstrate the baseline ability to detect the LFC T allele of rs without RE digestion. Right: The five spectra in the HpyCH4V group demonstrate the impact of RE digestion on T allele detection. Both DNAs used in the system are heterozygous for rs , which is not digestible by HpyCH4V.
The Journal of Molecular Diagnostics  , DOI: ( /j.jmoldx )
Copyright © 2011 American Society for Investigative Pathology and the Association for Molecular Pathology Terms and Conditions

4. Figure 3
Mixture-model studies of Tsp509I FI multiplexes. A: As shown by multiplex and SNP, the allele ratio of the nondigestible SNP allele is indicated with and without Tsp509I RE digestion of child-maternal DNA mixture pairs when maternal DNA is homozygous for the digestible allele and the child's DNA is heterozygous. INF, informative. B: A dot plot showing the number of informative SNP alleles detected for each DNA mixture. Each dot in the plot represents one mixed child-maternal pair or maternal-only DNA.
The Journal of Molecular Diagnostics  , DOI: ( /j.jmoldx )
Copyright © 2011 American Society for Investigative Pathology and the Association for Molecular Pathology Terms and Conditions

5. Figure 4
Performance of the Tsp509I FI assay panel on plasma DNA. A: A dot plot showing the number of informative SNPs detected in nonpregnant female and maternal plasma samples. B: Receiver operating characteristic (ROC) curve for the FI assay to detect LFC DNA in plasma as a function of the number of informative alleles detected. Each point in the ROC curve represents the number of informative alleles detected, with no informative alleles at the top right. FPR, false positive rate; INF, informative; TPR, true positive rate.
The Journal of Molecular Diagnostics  , DOI: ( /j.jmoldx )
Copyright © 2011 American Society for Investigative Pathology and the Association for Molecular Pathology Terms and Conditions