Cytogenetically Balanced Reciprocal Translocation Could Hide Molecular Genomic Unbalances: Implications for Foetal Phenotype Correlation

Diagnostics (Basel). 2024 Aug 9;14(16):1732. doi: 10.3390/diagnostics14161732.

Abstract

When an increased nuchal translucency (>3.00 mm) is observed during the echographic examination of a foetus in the first trimester of pregnancy, an increased risk of chromosomopathy is considered, and the pregnant woman is offered the possibility of an invasive investigation. Here, we focused our attention on prenatal diagnosis issues in cases of foetuses with cytogenetically balanced reciprocal translocations. We report the finding of a cytogenetically balanced, de facto genomically unbalanced translocation that poses a challenge in a case of prenatal diagnosis, changing the risk of Down syndrome in a Zellweger syndromic spectrum risk (PEX3 deletion). At term, a healthy baby was born. This case teaches that prenatal diagnosis in cases of foetuses at increased risk of chromosomal abnormality imperatively requires molecular investigation in addition to a morphological karyotype.

Keywords: PEX3 gene; chromosomal translocation; cytogenetic analysis; genomic comparative hybridisation array; genomic deletion; prenatal diagnosis.

Grants and funding

This research was funded by the University of Milano-Bicocca [2023-ATE-0402 and 2024-ATE-0194 to D.C.].