Detection of Trisomy 18 in a Fetal Tissue by Karyotyping and Chromosomal Microarray Analysis: A Case Report

We report the case of a 44-year-old woman who experienced a miscarriage. Fetal tissue obtained from the products of conception (POC) was analyzed to determine the genetic cause of pregnancy loss. Two complementary genetic testing methods were performed: conventional karyotyping and chromosomal microarray analysis (CMA). Karyotyping demonstrated an abnormal female karyotype, 47, XX +18, consistent with trisomy 18, while CMA identified a duplication of the entire chromosome 18, thereby confirming the presence of three copies of chromosome 18. The findings from both techniques were fully concordant and established trisomy 18 (Edward syndrome) as the cause of the miscarriage. This case highlights the value of combined cytogenetic and molecular genomics techniques to identify chromosomal anomalies and can be valuable for genetic counseling and for planning future pregnancies.