Noninvasively diagnosing for fetal trisomy 21 by examining heterozygous single nucleotide polymorphisms in the placental specific genes on chromosome 21

作者：Zhou, Fan; Liu, Shanling; Wang, He^*

来源：European Journal of Obstetrics & Gynecology and Reproductive Biology, 2019, 233: 19-25.

DOI：10.1016/j.ejogrb.2018.09.015

• Trisomy 21
• Placental-specific
• Massively parallel sequencing
• Noninvasive
• Diagnose

Objective: Noninvasive prenatal diagnosing for fetal trisomy 21 could help to avoid unnecessary amniocentesis. It is feasible to target the cell-free placental-specific mRNA in maternal plasma, thus eliminating the interference from the maternal genetic background. @@@ Study design: In this study, placental-specific genes on chromosome 21 were identified by searching the TiGER database and reviewing the published literature. These cell-free placental-specific mRNA fragments in maternal plasma were amplified and sequenced. Then, the allelic ratio of heterozygous single-nucleotide polymorphisms(SNPs) was analyzed. @@@ Results: Four placental-specific genes (DNMT3L, KRTAP26-1, PLAC4, DSCR4) were identified. This study included 42 cases of normal pregnancies and 19 cases of trisomy 21 pregnancies. The probability density function showed that the allelic ratio of heterozygous SNPs in normal pregnancy reached a peak at 1.0, and that in the trisomy 21 pregnancy was a double-peaked curve in both 0.5 and 2.0. However, the allelic ratio of heterozygous SNPs demonstrated no statistical difference between the normal and trisomy 21 pregnancies. @@@ Conclusion: Fetal trisomy 21 could not be diagnosed by examining the heterozygous SNPs of cell-free placental-specific mRNA on chromosome 21. This might be because the low quantity and quality of cell-free placental-specific mRNA fragments in maternal plasma, and the limited available heterozygous SNPs on the placental-specific genes.

• 出版日期2019-2
• 单位四川大学