Trisomy 8 mosaicism in chorionic villus sampling: Case report and counselling issues |
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Authors: | Jana Klein John M Graham Jr Lawrence D Platt Rhona Schreck |
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Institution: | 1. Medical Genetics—Birth Defects Center, Ahmanson Department of Pediatrics, Steven Spielberg Pediatrics Research Center, Cedars-Sinai Medical Center, UCLA School of Medicine, Los Angeles, CA 90048, U.S.A.;2. Department of Obstetrics and Gynecology, Cedars-Sinai Medical Center, UCLA School of Medicine, Los Angeles, CA 90024, U.S.A. |
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Abstract: | We report an unusual case involving chorionic villus sampling (CVS) and trisomy 8 mosaicism. CVS showed a normal direct preparation while the culture showed mosaicism for trisomy 8. Subsequent amniocentesis revealed only normal chromosomes. A peripheral blood culture after birth revealed low-level trisomy 8 mosaicism. The patient appeared phenotypically and developmentally normal at 30 months of age. We conclude that prenatal counselling for similar cases needs to include the rare but real possibility that chromosome mosaicism detected prenatally may be found postnatally with largely unknown consequences. Secondly, low-level chromosomal mosaicism may be more common than previously recognized. Thirdly, very low-level trisomy 8 mosaicism may be compatible with a normal phenotype but long-term follow-up is required. And lastly, the use of fetal blood sampling is questionable in these cases because the phenotype may not be accurately predicted. Further studies of such cases are needed to address these important and unanswered issues, including the potential implication of mosaicism on academic performance and cognitive functioning. |
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Keywords: | Chorionic villus sampling mosaicism trisomy 8 |
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