The Utility of Whole Exome Sequencing in Fetuses With Isolated Increased Nuchal Translucency
Hui Wang1, Caiqun Luo1, Qian Geng2
1Maternal-Fetal Medicine Centre, Shenzhen Maternity and Child Healthcare Hospital, Shenzhen, China.
Background:
To evaluate the utility of prenatal whole exome sequencing (WES) in cases of isolated increased nuchal translucency (NT).
Methods:
Retrospective analysis of the prenatal WES results in fetuses with increased NT (≥ 3.0 mm) and normal fetal anatomy, normal karyotype, and chromosomal microarray analysis (CMA). Subgroup analysis was performed based on NT measurements.
Results:
Diagnostic variants were identified in 3 of 118 fetuses (2.5%) with isolated increased NT (≥ 3.0 mm). The distribution of positive findings was as follows: NT 3.0-3.4 mm group (n = 13): 1 case (7.7%) with diagnostic genetic variants; NT ≥ 3.5 mm group (n = 105): 2 cases (1.9%) with diagnostic genetic variants (both in the NT 5.0-6.4 mm subgroup). Fisher's exact test (two-tailed) showed no statistically significant differences in diagnostic yield between: NT 3.0-3.4 mm versus NT ≥ 3.5 mm (p = 0.298); NT 3.0-3.4 mm versus NT 5.0-6.4 mm (p = 1.000); NT ≥ 3.0 mm versus NT ≥ 3.5 mm (p = 1.000).
Conclusion:
Our analysis revealed a low diagnostic yield (2.5%) for prenatal WES in cases of isolated increased NT ≥ 3.0 mm. Our findings provide valuable evidence for clinical counseling, particularly when patients inquire about the likelihood of isolated findings. These data offer meaningful guidance for their decision-making process regarding further testing options.
