Table 2.
Distribution of chromosomal abnormalities detected by quantitative fluorescent polymerase chain reaction (QF-PCR) and chromosomal microarray analysis (CMA) of 499 amniotic fluid samples from pregnancies with a nuchal translucency (NT) ≥2.5 mm.
| NT (mm) | N (%) | Aneuploidies and triploidy detected by QF-PCR | Pathogenic | CNVs | VOUS | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Trisomy 21 | Trisomy 18 | Trisomy 13 | Monosomy X | Trisomy 21 mosaicismb | Monosomy X mosaicismb | Triploidyb | ≥10 Mb | <10 Mb | |||
| 2.5 mm ≤ NT < 3.0 mm | 134 (26.9) | 2 | 1 | 1 | 0 | 1 | 2 | 0 | 1 | 3 | 1 |
| 3.0 mm ≤ NT < 3.5 mm | 146 (29.3) | 6 | 1 | 0 | 1 | 0 | 0 | 0 | 0 | 2 | 0 |
| 3.5 mm ≤ NT < 4.5 mm | 140 (28.0) | 14 | 6 | 0 | 3 | 0 | 0 | 0 | 0 | 7 | 0 |
| 4.5 mm ≤ NT < 5.5 mm | 32 (6.4) | 3 | 2 | 0 | 0 | 0 | 0 | 0 | 2 | 0 | 0 |
| 5.5 mm ≤ NT < 6.5 mm | 13 (2.6) | 4 | 0 | 0 | 1 | 0 | 0 | 1 | 1 | 1 | 0 |
| 6.5 mma ≤ NT | 34 (6.8) | 4 | 6 | 1 | 5 | 0 | 0 | 0 | 2 | 2 | 0 |
aNineteen cases diagnosed with cystic hygroma were classified in this group. bOne case of trisomy 21 mosaicism, two cases of monosomy X mosaicism, and one case of triploidy were further confirmed by fluorescence in situ hybridization (FISH).