PMC9549001_01
Identification of the marker chromosomes with direct examination of the cytotrophoblast following CVS [revealed two supplementary and identical SMCs (48,XX,+marx2)].
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F1
Direct analysis of short-term cultured chorionic villi with conventional RHG banding revealed two homogeneous, supernumerary and identical SMCs: 48,XX,+marx2 (Figure 1).
Identification of the marker chromosomes with interphasic FISH using centromeric probe of chromosome 20 (showing tetrasomy 20 in 20% of nuclei; lens 100X).
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F2
Metaphase FISH with the 20 centromeric probe was normal in 25/25 mitoses, but interphase FISH found segmental tetrasomy 20 in 20% of the 100 examined nuclei (Figure 2).
Patient's analysis workflow by weeks of amenorrhea. US, ultrasound; MSS, maternal serum screen, CVS, chorionic villus sampling, NIPT, noninvasive prenatal testing; FISH, fluorescence in situ hybridization.
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F3
A analysis flowchart for the patient is shown in Figure 3.