Chromosomal aberrations are frequently associated with birth defects and pregnancy losses. Trisomy 13, Trisomy 18 and Trisomy 21 are the most common, clinically relevant fetal aneusomies. This study used a transcriptomics approach to identify the molecular signatures at the maternal–fetal interface in each aneuploidy.METHODS
We profiled placental gene expression (13–22 weeks) in T13 (n = 4), T18 (n = 4) and T21 (n = 8), and in euploid pregnancies (n = 4).RESULTS
We found differentially expressed transcripts (≥2-fold) in T21 (n = 160), T18 (n = 80) and T13 (n = 125). The majority were upregulated and most of the misexpressed genes were not located on the relevant trisomic chromosome, suggesting genome-wide dysregulation. A smaller number of the differentially expressed transcripts were encoded on the trisomic chromosome, suggesting gene dosage. In T21, <10% of the genes were transcribed from the Down syndrome critical region (21q21–22), which contributes to the clinical phenotype. In T13, 15% of the upregulated genes were on the affected chromosome (13q11–14), and in T18, the percentage increased to 24% (18q11–22 region).CONCLUSION
The trisomic placental (and possibly fetal) phenotypes are driven by the combined effects of genome-wide phenomena and increased gene dosage from the trisomic chromosome. © 2016 John Wiley & Sons, Ltd.
Funding sources: Dr. Katherine Bianco was supported by a Reproductive Scientist Development Program Award (K12HD000849) and a Clinical Investigator Award (K08HD069518-01). Placental tissue samples were provided by the NIH Placental Bank at UCSF, funded under NIH U54 HD055764.
Conflicts of interest: None declared