Abstract:Abstract Objective: To explore the clinical value of prenatal ultrasound in suggesting thickening of the nuchal translucency in the fetus and to compare the results with those of genetic prenatal diagnosis. Methods: The results of ultrasound and genetic prenatal diagnosis of 106 fetuses with thickening of the nuchal translucency at our institution were compared and analyzed (all fetuses were subjected to chromosomal microarray analysis, with whole-exome sequencing in four cases and SMN1 gene testing in one case), and pregnancy outcomes were followed. Results: A total of 44 (41.51%) cases of genetic abnormalities and 2 cases of copy number variants of unknown clinical significance were identified. A total of 39 chromosomal abnormalities (34 aneuploidy abnormalities and 5 pathogenic copy number variants) and 5 genetic abnormalities (all pathogenic or suspected pathogenic variants) were included in those with genetic abnormalities. The incidence of genetic abnormalities increased significantly with increasing thickness of the nuchal translucency. In addition, 38 (86.36%) of 44 fetuses with genetic abnormalities were combined with other ultrasound abnormalities, with the highest percentage of nasal bone dysplasia.Conclusions: The incidence of genetic abnormalities is significantly increased in thickened nuchal translucency, and chromosomal abnormalities, especially aneuploidy, should be the first consideration in the detection of thickened nuchal translucency. NT thickening is also associated with copy number variation and certain monogenic inherited diseases . For Chromosome microarray analysis negative NT thickening fetus, can be combined with ultrasound and family history of comprehensive to thewhole-exome sequencing.