Abstract:

We report a case of pregnant woman with fetal growth restriction (FGR). In this case, non-invasive prenatal testing showed the excessive chromosome 16, and the amniotic fluid genome copy number variants sequencing showed 16 trisomy mosaicism (16%). The pregnant woman came to our hospital at 37⁺² weeks of gestation because the fetus was less than 3 weeks of gestational weeks. Emergency cesarean section was operated due to fetal distress. The newborn was a full-term low birth weight infant. The karyotype analysis and high-throughput sequencing of neonatal peripheral blood and placenta samples at multiple sites showed that the neonatal karyotype was 46, XX, 16qh+, and that the placenta tests were trisomy 16 mosaicism. Follow-up to five months after birth, the child was currently growing and developing normally. This case and literature suggest that it is necessary to combine FISH or SNP array when only CNV-Seq test showed chromosomal mosaicism by amniocentesis, to monitor ultrasound closely and give reasonable genetic counseling. The confined placental mosaicism of trisomy 16 can cause placental dysfunction and FGR.

Key words: Fetal growth retardation, Fetal distress, Amniocentesis, Prenatal diagnosis, Confined placental mosaicism, High-throughput sequencing