Confined placental mosaicism and pregnancy outcome: a distinction needs to be made between types 2 and 3

Authors

  • Jérôme Toutain,

    Corresponding author
    1. Cytogenetic Laboratory, Department of Medical Genetics, Pellegrin University Hospitals (Maternity), Place Amélie Raba-Léon, 33076 Bordeaux, France
    2. University Victor Segalen (Bordeaux 2), 146 rue Léo Saignat, 33076 Bordeaux, France
    • Laboratoire de Cytogénétique, Service de Génétique Médicale, Maternité Pellegrin, CHU de Bordeaux, Place Amélie Raba-Léon Bordeaux 33076, France.
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  • Cécile Labeau-Gaüzere,

    1. University Victor Segalen (Bordeaux 2), 146 rue Léo Saignat, 33076 Bordeaux, France
    2. Department of Obstetrics and Gynecology, Pellegrin University Hospitals (Maternity), Place Amélie Raba-Léon 33076 Bordeaux, France
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  • Thomas Barnetche,

    1. Department of Rheumatology, Pellegrin University Hospitals, Place Amélie Raba-Léon 33076 Bordeaux, France
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  • Jacques Horovitz,

    1. University Victor Segalen (Bordeaux 2), 146 rue Léo Saignat, 33076 Bordeaux, France
    2. Department of Obstetrics and Gynecology, Pellegrin University Hospitals (Maternity), Place Amélie Raba-Léon 33076 Bordeaux, France
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  • Robert Saura

    1. Cytogenetic Laboratory, Department of Medical Genetics, Pellegrin University Hospitals (Maternity), Place Amélie Raba-Léon, 33076 Bordeaux, France
    2. University Victor Segalen (Bordeaux 2), 146 rue Léo Saignat, 33076 Bordeaux, France
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Abstract

Objective

To study the influence of types 2 and 3 confined placental mosaicism (CPM) on pregnancy outcome.

Method

From 13 809 chorionic villus samplings (CVSs), karyotype after long-term cultured villi (LTC-villi) was systematically performed. Next, in case of suspicion of CPM, karyotype after short-term cultured villi (STC-villi) was established to define type 2 CPM (chromosomal abnormality limited to the mesenchymal core) or type 3 CPM (chromosomal abnormality found both in the cytotrophoblast and the mesenchymal core). Confirmatory amniocentesis was performed to exclude fetal mosaicism. Uniparental disomy (UPD) testing was carried out when the abnormal cell line involved chromosomes 5, 6, 7, 15 or 16.

Results

Fifty-seven CPM cases were observed (57/13 809 = 0.41%) and of these, 37 were type 2 and 20 were type 3 CPM. Incidence of preterm infants, neonatal hypotrophy and adverse pregnancy outcome were comparable between patients in whom type 2 CPM was demonstrated and the control population. In contrast, for the type 3 CPM the incidence of these factors was higher than for the control population.

Conclusion

When a CPM is suspected, it appears essential to determine type, since type 2 has no effect on fetal development and type 3 is associated with preterm infants, low birth weight and adverse pregnancy outcome. Copyright © 2010 John Wiley & Sons, Ltd.

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