胎盘嵌合型16三体合并胎儿生长受限一例

报告1例胎儿生长受限(fetal growth restriction,FGR)孕妇,该孕妇因无创产前筛查提示16号染色体偏多行产前诊断,羊水基因组拷贝数变异测序(copy number variants sequencing,CNV-Seq)结果显示16三体嵌合体(16%)。孕37+2周因胎儿小于孕周3周于天津市中心妇产科医院就诊,因胎儿宫内窘迫行急诊剖宫产,新生儿为足月小样低体质量儿。对新生儿外周血及胎盘多位点取样分别进行核型分析和高通量测序,结果显示新生儿核型为46,XX,16qh+,胎盘检测结果为16三体嵌合体。随访至出生5个月,生长发育正常。该病例及文献复习提示羊水穿刺仅CNV-Seq一项检测显示染色体嵌合体者,有必要结合荧光原位杂交技术或单核苷酸多态性-微阵列比较基因组杂交技术验证,并密切监测超声,给予合理的遗传咨询;限制性胎盘嵌合型16三体引起胎盘功能障碍可导致FGR。

A Case of Confined Placental Mosaicism of Trisomy 16 Combined with Fetal Growth Restriction

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.