We report on ten pregnancies with trisomy 8 mosaicism. Nine cases were prenatally detected in chorionic villi (n = 6), amniotic fluid (AF) cells (n = 2) or fetal blood (FB) lymphocytes (n = 1). Follow-up laboratory investigations showed confined placental mosaicism (CPM) or pseudomosaicism in eight cases. In one case with ultrasound abnormalities, trisomy 8 mosaicism was detected in FB cells although cultured AF cells showed normal cells only. Another case of mosaic trisomy 8 was prenatally missed; cytogenetic analysis of short-term cultured villi revealed a normal male karyotype, while postnatally, trisomy 8 mosaicism was detected in peripheral blood lymphocytes and skin fibroblasts of the affected child. These findings indicate the difficulties in the prenatal diagnosis of trisomy 8 mosaicism. When found in chorionic villi, it mostly represented CPM, while in a case of true fetal trisomy 8 mosaicism, the cytotrophoblast cells showed a normal karyotype. So, the cytotrophoblast compartment of chorionic villi is a poor indicator of the presence or absence of fetal trisomy 8 mosaicism. Follow-up investigations including amniocentesis and especially fetal blood sampling are required to come to a definite prenatal diagnosis of trisomy 8 mosaicism. Copyright

, ,
doi.org/10.1002/pd.215, hdl.handle.net/1765/71292
Prenatal Diagnosis
Department of Clinical Genetics

van Haelst, M., Van Opstal, D., Lindhout, D., & Los, F. J. (2001). Management of prenatally detected trisomy 8 mosaicism. Prenatal Diagnosis, 21(12), 1075–1078. doi:10.1002/pd.215