Prenatal whole‐exome sequencing in fetuses with increased nuchal translucency

BACKGROUND: Increased nuchal translucency (NT) is associated with an increased risk for genetic disorders. The aim of this study was to investigate the value of whole‐exome sequencing (WES) in detecting genetic abnormalities for fetuses with isolated first‐trimester increased NT. METHODS: After the exclusion of aneuploidies and pathogenic copy number variants (CNVs) by quantitative fluorescent polymerase chain reaction (QF‐PCR) and chromosomal microarray analysis (CMA), WES was performed on 63 fetuses with isolated first‐trimester increased NT (≥3.5 mm). RESULTS: Overall, WES yielded a 4.8% (3/63) diagnostic rate for fetuses with isolated increased NT. Pathogenic variants were identified in 37.5% (3/8) fetuses that developed additional structural anomalies later in gestation, and no pathogenic variants were detected in increased NT that resolved or remained isolated throughout the pregnancy. CONCLUSION: This study provides powerful evidence to offer prenatal WES for increased NT only when additional abnormalities are present. Early detailed ultrasound to detect emerging anomalies can help physicians offer prenatal WES to fetuses with a greater likelihood of diagnosis.