De novo small supernumerary marker chromosomes detected on 143 000 consecutive prenatal diagnoses: chromosomal distribution, frequencies, and characterization combining molecular cytogenetics approaches. (11th February 2014)

• Record Type: Journal Article
• Authors: Malvestiti, Francesca; De Toffol, Simona; Grimi, Beatrice; Chinetti, Sara; Marcato, Livia; Agrati, Cristina; Di Meco, Anna Maria; Frascoli, Giuditta; Trotta, Anna; Malvestiti, Barbara; Ruggeri, Anna; Dulcetti, Francesca; Maggi, Federico; Simoni, Giuseppe; Grati, Francesca Romana
• Is Part Of: Prenatal diagnosis. Volume 34:Number 5(2014:May)
• Page Start: 460
• Page End: 468
• Publication Date: 2014-02-11
• Subjects: Prenatal diagnosis -- Periodicals; Fetus -- Diseases -- Diagnosis -- Periodicals; Electronic journals; 618.32075
• DOI: 10.1002/pd.4330
• Languages: English
• ISSNs: 0197-3851

Abstract

<abstract abstract-type="main"> <title>ABSTRACT</title> <sec id="pd4330-sec-0001" sec-type="section"> <title>Objective</title> <p>The risk of clinical consequences in prenatal cases with <italic>de novo</italic> small supernumerary marker chromosomes (sSMC), often in mosaic conditions, is not easy to predict, which results in difficulties in genetic counseling.</p> </sec> <sec id="pd4330-sec-0002" sec-type="section"> <title>Method</title> <p>In this study, we evaluated the frequency, the chromosomal origin, and the clinical indication of 104 <italic>de novo</italic> sSMC detected in a monocenter survey on the basis of 143 000 consecutive prenatal diagnoses, and we assessed the reliability of molecular cytogenetics technologies for sSMC characterization.</p> </sec> <sec id="pd4330-sec-0003" sec-type="section"> <title>Results</title> <p>We detected a <italic>de novo</italic> sSMC frequency of 0.072%. Its incidence in advanced maternal age group is statistically different from that found in maternal anxiety indication (<35 years old). A higher prevalence of mosaicism in chorionic villi sampling (CVS) than in amniotic fluids was also revealed related to confined placental mosaicisms. The risk of confirmation in amniotic fluids of mosaics previously revealed at CVS was 33.3%. No uniparental disomy conditions were found when imprinted chromosomes were involved in the occurrence of <italic>de novo</italic> sSMC. The majority of <italic>de novo</italic> sSMC were acrocentric derived‐chromosomes, and a neocentromere formation was observed in one pregnancy.</p> </sec> <sec id="pd4330-sec-0004" sec-type="section"> <title>Conclusion</title> <p>Our data support that array comparative genomic hybridization has improved sSMC characterization and demonstrate its utility in supporting genetic counseling. We propose a workflow for <italic>de novo</italic> sSMC characterization. © 2014 John Wiley & Sons, Ltd.</p> </sec> </abstract>