Table 1.
Positive Predictive Values for Noninvasive Prenatal Screening Performed at Third-party Laboratories
Fig 1.
Relationship of fetal fraction estimated using a median of X and Y based methods with the fetal fraction estimated from a model of autosomal read counts among 1366 male samples that were not included in the development of the autosomal model.
Pearson correlation coefficient (r) = 0.81.
Table 2.
Follow-up of Clinical Samples Positive for Fetal Aneuploidies on Non-invasive Prenatal Screening
Fig 2.
Z scores of the laboratory-developed noninvasive prenatal assay for trisomies 21, 18, and 13 before (raw) and after correction for GC content and statistical smoothing using a proprietary software algorithm.
The assay provided complete discrimination between affected and unaffected pregnancies for trisomy 21, even without adjustments. GC correction and statistical smoothing eliminated the substantial overlap between affected and unaffected pregnancies for trisomies 18 and 13, and enhanced separation for trisomy 21.
Fig 3.
Ideogram for chromosome 21 from a prenatal sample positive for trisomy 21.
Each point represents a normalized count for a particular bin on a particular chromosome; a euploid value on the Y axis is 1.0. As can been seen, the entire chromosome 21 demonstrated duplicated material. The Z score for this sample was 36.96.
Fig 4.
Ideogram for chromosome 21 from a patient with a maternal microduplication.
Fig 5.
Microarray data for maternal DNA for the patient in Fig 4.
Fig 6.
Ideogram for chromosome 18 from a patient with a maternal microduplication.
Fig 7.
Microarray data for maternal DNA for the patient in Fig 6.
Fig 8.
Ideogram for chromosome 22 from a patient with a fetal microdeletion in the DiGeorge region.