Prenatal manifestations of 3q29 deletion: A potential relationship with enlarged nuchal translucency

The 3q29 deletion syndrome is characterized by neurodevelopmental and/or psychiatric manifestations after birth. Few cohort studies have been focused on prenatal manifestations of this syndrome.

This study is aimed to reveal the prenatal manifestations of 3q29 deletion syndrome.

In this 5-year retrospective cohort study, gravidas with singleton pregnancies who underwent invasive prenatal diagnosis via single nucleotide polymorphism array for chromosomal abnormalities were included. First-trimester ultrasound screening was performed at 11⁺⁰--13⁺⁶ weeks' gestation for all included gravidas, and detailed mid-trimester fetal anomaly scans were performed at 20⁺⁰--24⁺⁰ weeks' gestation.

The prevalence of 3q29 deletion was 0.24 per thousand (9/36,978) in the prenatal period. Approximately 77.78 % (7/9) fetuses with 3q29 deletion were observed with unseptate enlarged nuchal translucency (NT) without major heart defects. Except for one was inherited from the gravidas with mild intellectual disability, all the other eight were proven to be de novo. The incidence of 3q29 deletion in fetuses with enlarged NT was significantly higher than those without enlarged NT (P < 0.001).

The 3q29 deletion was enriched in fetuses with enlarged NT. Enlarged NT was the most specific prenatal presentation for 3q29 deletions.