Application of chromosomal microarray in fetuses with increased nuchal translucency

Objective: To evaluate submicroscopic chromosomal abnormalities in fetuses with increased nuchal translucency (NT) and normal karyotype.Methods: A total of 319 fetuses with increased NT (≥3.0 mm) were tested using conventional karyotyping. When cytogenetic analysis showed normal chromosomes, the parents then received a consultation for chromosomal microarray (CMA) analysis, and a subsequent morphology scan was performed between 20 and 24 weeks gestation. Submicroscopic chromosomal abnormalities were assessed and compared between the fetuses with and without structural defects. Likewise, the prevalence of pathologic copy number variants (CNVs) among cases with increased NT was compared with the 926 low-risk cases consisted of patients whose sole indication for testing was advanced maternal age.Results: Chromosomal abnormality was identified in 32.29 (103/319) of fetuses, and 137 samples were tested using CMA. Additional pathogenic copy number variants (CNVs) were also detected in 5.12% (7/137) of t...