Variants in maternal effect genes and relaxed imprinting control in a special placental mesenchymal dysplasia case with mild trophoblast hyperplasia

Tien Chi Huang, Kung Chao Chang, Jen Yun Chang, Yi Shan Tsai, Yao Jong Yang, Wei Chun Chang, Chu Fan Mo, Pei Hsiu Yu, Chun Ting Chiang, Shau Ping Lin, Pao Lin Kuo

Research output: Contribution to journalArticlepeer-review

Abstract

Placental mesenchymal dysplasia (PMD) and partial hydatidiform mole (PHM) placentas share similar characteristics, such as placental overgrowth and grape-like placental tissues. Distinguishing PMD from PHM is critical because the former can result in normal birth, while the latter diagnosis will lead to artificial abortion. Aneuploidy and altered dosage of imprinted gene expression are implicated in the pathogenesis of PHM and also some of the PMD cases. Diandric triploidy is the main cause of PHM, whereas mosaic diploid androgenetic cells in the placental tissue have been associated with the formation of PMD. Here, we report a very special PMD case also presenting with trophoblast hyperplasia phenotype, which is a hallmark of PHM. This PMD placenta has a normal biparental diploid karyotype and is functionally sufficient to support normal fetal growth. We took advantage of this unique case to further dissected the potential common etiology between these two diseases. We show that the differentially methylated region (DMR) at NESP55, a secondary DMR residing in the GNAS locus, is significantly hypermethylated in the PMD placenta. Furthermore, we found heterozygous mutations in NLRP2 and homozygous variants in NLRP7 in the mother’s genome. NLRP2 and NLRP7 are known maternal effect genes, and their mutation in pregnant females affects fetal development. The variants/mutations in both genes have been associated with imprinting defects in mole formation and potentially contributed to the mild abnormal imprinting observed in this case. Finally, we identified heterozygous mutations in the X-linked ATRX gene, a known maternal–zygotic imprinting regulator in the patient. Overall, our study demonstrates that PMD and PHM may share overlapping etiologies with the defective/relaxed dosage control of imprinted genes, representing two extreme ends of a spectrum.

Original languageEnglish
Article number544
JournalBiomedicines
Volume9
Issue number5
DOIs
Publication statusPublished - 2021 May

All Science Journal Classification (ASJC) codes

  • Medicine (miscellaneous)
  • Biochemistry, Genetics and Molecular Biology(all)

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