A placental trisomy 2 detected by NIPT evolved in a fetal small Supernumerary Marker Chromosome (sSMC)

Abstract Background Non-invasive prenatal testing (NIPT) is a rapidly developing and widely used method in the screening. Recently, widespread use of NIPT caused neglecting limitations this technology. Case presentation The 38-year-old woman underwent amniocentesis because high risk trisomy 2 revealed by genome-wide Non-Invasive Prenatal Test (NIPT). invasive diagnosis mosaicism for small supernumerary marker chromosome sSMC derived from 2. Interphase fluorescence situ hybridization (FISH) on uncultured amniocytes three signals centromere 30% cells. GTG-banded metaphases abnormal karyotype (47,XX,+mar[21]/46,XX[19]) was confirmed array comparative genomic (aCGH). Cytogenetic analyses (FISH, aCGH, karyotype) fetal skin biopsies were performed gain centromeric region In placenta, cell lines detected: normal line, line with third one only sSMC. Conclusion Whole-genome Testing allows not identification common trisomies but also rare chromosomal abnormalities. Especially such cases, it extremely important to perform verification sample material other than trophoblast, apply appropriate research methods. Such conduct detailed analysis detected aberration, thus clinical validity.