NORMAL OUTCOME OF A PREGNANCY WITH MOSAICISM FOR DOUBLE TRISOMY IN AMNIOTIC-FLUID CELLS

True chromosomal mosaicism of double trisomy (48, XX, +7, +20) was det ected in amniotic fluid cell cultures at 16 and 20 weeks of gestation. No aneuploid cells were found in chorionic villus samples (CVS) by se midirect preparation and long-term culture. High-level ultrasound did not indicate any structural abnormality of the fetus. At 38 weeks of g estation, a phenotypically normal girl was born. She is now 22 months old and normally developed. At birth, various samples were investigate d by routine cytogenetic methods or by fluorescence in situ hybridizat ion with the probe p7t1 (umbilical cord blood, placental tissue, umbil ical cord fibroblasts, urine sediment) and no abnormal cells could be detected in any of those tissues. (C) 1997 by John Wiley & Sons, Ltd.