PMC9797983_01
Non- invasive prenatal testing (NIPT) data in case 1.
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F1
After adequate genetic counseling, NIPT was performed at 11 + 0 weeks of pregnancy, and the result showed a high risk of trisomy 21 (FF = 6.98%, 21 chromosome Z-score = 3.6) (Figure 1).
QF-PCR and conventional karyotyping results in case 1. (A) QF-PCR analysis for chromosome 21 of uncultured chorionic villi. (B) Conventional karyotype analysis of uncultured chorionic villi; 47, XX, +21[11]/46, XX [39]. (C) QF-PCR result for chromosome 21 of uncultured amniocytes. (D) Conventional karyotype analysis of cultured amniocytes; 46, XX.
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F2
The patient underwent QF-PCR and karyotyping at 14 + 0 weeks of pregnancy through CVS and exhibited a normal pattern in QF-PCR (Figure 2A) and mosaicism of 47, XX, +21[11] and 46, XX [39] (Figure 2B). Owing to the discrepancy between the NIPT and CVS results, the patient underwent amniocentesis at 15 + 6 weeks, and showed a normal pattern in QF-PCR (Figure 2C) and 46, XX karyotyping in long-term culture (Figure 2D).
UPD test for chromosome 21 using QF-PCR in case 1. (A) Fetus allele in uncultured amniocytes; UPD of chromosome 21 was not detected. (B) Maternal allele in peripheral blood. (C) Paternal allele in peripheral blood.
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F3
UPD. UPD of chromosome 21 was not detected in the amniotic fluid sample (Figure 3).
(A-G) QF-PCR result for chromosome 21 in each location of placenta in case 1 (A) cord blood, (B) chorion, (C) villus parenchyma (fetal side section), (D) villus parenchyma (middle section), (E) villus parenchyma (maternal side section I), (F) villus parenchyma (maternal side section II), (G) amnion.
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F4
After delivery, we sampled 7 x 1 cm3 positions of the placenta and checked chromosome 21 using QF-PCR (Figures 4A-G). However, trisomy 21 was identified in the placental region close to the mother, including in the amniotic membrane (Figures 4A-G).
PMC9797983_02
Non- invasive prenatal testing (NIPT) data in case 2 (A) 1st trial data (B) re-test data.
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F5
Re-sampling was performed at 16 + 5 weeks of pregnancy, and the results showed a intermediate risk of trisomy 21 (FF = 7.52%, 21 chromosome Z-score = 2.503) (Figure 5A). We repeated the experiment on this sample to exclude a false positive result, and the results again showed a intermediate risk of trisomy 21 again (FF = 7.02%, 21 chromosome Z-score = 2.62) (Figure 5B).
QF-PCR and conventional karyotyping results in case 2. (A) QF-PCR result for chromosome 21 of uncultured amniocytes. (B) Conventional karyotype analysis of cultured amniocytes; 47, OO, +21[22]/46, OO [4].
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F6
Trisomy 21 was detected by QF-PCR (Figure 6A), and mosaicism of 47, XX, + 21[22]/46, XX [4] was detected by karyotyping (Figure 6B).
(A-G) QF-PCR result for chromosome 21 sampling each location of placenta in case 2 (A) cord blood, (B) chorion, (C) villus parenchyma (fetal side section), (D) villus parenchyma (middle section), (E) villus parenchyma (maternal side section I), (F) villus parenchyma (maternal side section II), (G) amnion.
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F7
Samples were collected from 7 x 1 cm3 positions of the placenta (Figure 7). QF-PCR in one of the samples showed three of the samples showed trisomy 21 (Figures 7A, D, F) and the remaining four samples showed a mosaic pattern (Figures 7B, C, E, G).