Distribution of NT in cohort 2 (mutation-negative versus mutation-positive samples)
| NT (mm) | Mutation-negative samples (n=168) (n(%)) | Mutation-positive samples (n=25) (n(%)) |
| < 3.5 | 3 (2) | 1 (4) |
| 3.5– 3.9 | 25 (15) | 2 (8) |
| 4.0– 4.9 | 22 (13) | 0 (0) |
| 5.0– 5.9 | 21 (12.5) | 1 (4) |
| 6.0– 6.9 | 6 (4) | 3 (12) |
| 7.0– 7.9 | 4 (2) | 1 (4) |
| > 8.0 | 10 (6) | 11 (44) |
| Increased, but unknown | 21 (12.5) | 4 (16) |
| Nuchal fold at 20 weeks of gestational age | 34 (20) | 1 (4) |
| Not measured | 22 (13) | 1 (4) |
NT, nuchal translucency.