Parental mosaic trisomy 21 detected following maternal cell contamination of an amniotic fluid specimen from a normal male pregnancy |
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Authors: | Melissa L Street John C K Barber Tracy A Boyle Katrina H Ellis Hilary Bullman Tessa Homfray |
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Institution: | 1. Wessex Regional Genetics Laboratory, Salisbury District Hospital, Odstock Road, Salisbury, Wiltshire, SP2 8BJ, UK;2. St. George's Hospital, Blackshaw Road, Tooting, London, SW17 0QT, UK |
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Abstract: | We report a case of maternal mosaic trisomy 21 ascertained at prenatal diagnosis as a result of maternal cell contamination of an amniotic fluid sample. A 34 year old female was referred for karyotyping because of a previous trisomy 21 pregnancy. Chromosome analysis of primary in situ cultures showed a karyotype of 47,XX, + 216]/46,XY32]/46,XX2]. Molecular testing demonstrated maternal cell contamination of the amniotic fluid sample and G-banded karyotyping of maternal blood showed that 3/200 cells had trisomy 21, consistent with the mother being a Down syndrome mosaic. A normal male baby with a 46,XY chromosome complement was delivered at 30 weeks. This case emphasises the need for close collaboration between cytogenetic and molecular genetics laboratories in resolving unusual cases of mosaicism. Copyright © 2007 John Wiley & Sons, Ltd. |
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Keywords: | trisomy 21 maternal cell contamination mosaicism prenatal diagnosis amniocentesis |
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