Fig. 2: Cell-free fetal DNA (cffDNA) haplotyping analysis for monogenic disorders.
From: Noninvasive prenatal diagnosis by genome-wide haplotyping of cell-free plasma DNA
Disease locus associated chromosome cffDNA haplotyping result. For each subfigure, family pedigree information is displayed together with haplotyping. The reference haplotypes from either the born child and/or from the embryo blastomere and cffDNA haplotyping results are shown. Blue in haplotype plots indicates paternal haplotype inheritance and red indicates maternal haplotype inheritance. For cffDNA haplotyping results, both segmented fetal allele ratio (FAR) values and derived haplotype blocks are shown. In segmented FAR values track, the red dotted line represents segmented P1 or M1 FAR and blue for segmented P2 or M2 FAR, and the distance between P1 and P2 or M1 and M2 segmentation in the same genomic region indicates fetal fraction. We flipped FAR values of P1 subcategory around 0 and FAR values of M1 were subjected to less than or equal to 0 in visualization for clear separation between informative single-nucleotide polymorphism (SNP) subcategories. Disease loci are indicated by a yellow vertical line. (a) cffDNA haplotype compared with neonate haplotype and embryo haplotype. The paternal homolog carrying the variant is represented in dark blue and maternal homolog carrying the variant is represented in dark red. The disease locus resided in the light color block of both paternal and maternal haplotypes, indicating wild-type alleles were transmitted. (b, c) cffDNA haplotyping results compared with the embryo haplotype. (b) Two disease indications of the family are shown. (c) Inheritance of an X-linked disorder is shown. PGT preimplantation genetic testing.
