Monozygotic twins discordant for trisomy 21 and maternal 21q inheritance: a complex series of events

Article Article scientifique Article Monozygotic twins discordant for trisomy 21 and maternal 21q inheritance: a complex series of events eng 2008 author Dahoun Sophie 22913 author Gagos Sarantis 561306 author Gagnebin Maryline 104300 author Gehrig Corinne 86500 author Burgi Taboada Merino Carole 523996 author Simon Fabienne 78213 author Vieux-Pfenninger Chantal Brigitte Anne 108066 author Extermann Philippe 22851 author Lyle Robert 519786 author Morris Michael Andréw 24090 author Antonarakis Stylianos 22813 author Bena Frédérique author Blouin Jean-Louis 513663 2086-2093 10.1002/ajmg.a.32431 18627064 1552-4825 We report on a monochorionic/diamniotic twin pregnancy discordant for trisomy 21. Amniocentesis (at 13(5/7) weeks) was performed following ultrasound signs of hydrops and cystic hygroma in twin 1 (T1). Prenatal karyotype showed non-mosaic trisomy 21 in T1 (47,XX,+21[7]), and low-grade mosaic trisomy 21 in twin 2 (T2) (47,XX,+21[2]/46,XX[19]). Post mortem examination of fetal skin, kidneys and lungs confirmed trisomy 21 in T1 (47,XX,+21[548]) and the placenta (47,XX,+21[200]). T2 had a normal karyotype (46,XX[648]). Analysis of microsatellite polymorphisms in multiple samples from the placenta, hand, lungs, kidneys and the umbilical cords of both twins confirmed monozygosity for all loci tested, and trisomy 21 in T1. Unexpectedly, T1 and T2 inherited different maternal alleles for markers of the most distal 4 Mbp of 21q. At least four successive events are needed to explain the genetic status of both twins and include maternal MI premature chromatids separation or maternal II meiotic nondisjunction and post-zygotic events such as, chromosome rescue, nondisjunction, an/or recombination. Amniocentesis Chromosomes, Human, Pair 21/genetics Diseases in Twins Down Syndrome/genetics Female Genetic Markers Genotype Humans Karyotyping Microsatellite Repeats Nondisjunction, Genetic Polymorphism, Genetic Pregnancy Prenatal Diagnosis Twins, Monozygotic Dewey 576.5 135 Département de médecine génétique et développement 21D false 196 Pathologie Moléculaire de la Trisomie 21 et le Génome Humain 248 American journal of medical genetics. Part A 146A 16 726a7285-1a6b-4fae-baa4-2c6281c3f19f Article (Accepted version) Restricted Article.pdf 282842 application/pdf restrictedAccess Faculté de médecine / Section de médecine fondamentale / Département de médecine génétique et développement

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Monozygotic twins discordant for trisomy 21 and maternal 21q inheritance: a complex series of events	American journal of medical genetics. Part A			2008	630	4

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Simon, Fabienne