Rare non-mosaic trisomies in chorionic villus tissue not confirmed at amniocentesis.
This paper reports eight cases of non-mosaic, rare, and typically lethal trisomies diagnosed in chorionic villi and not confirmed by amniocentesis. Four cases were 47,XX,+16; two cases were 47,XX,+2; one was 47,XX,+12; and one was 47,XY,+7. There have been no known complications in any of these gestations. These eight cases were found in a series of approximately 12,000 samples processed in our laboratory (0.07 per cent). We conclude that (1) rare non-mosaic trisomy not reflecting the fetal condition is an occasional source of diagnostic ambiguity in chorionic villus sampling; and (2) when encountered, a follow-up amniocentesis should be recommended to the patient to confirm or rule out the abnormality. We propose the term 'confined placental abnormality' to describe non-mosaic trisomies and other related abnormalities found only in chorionic tissue.
Dorfmann
A D
AD
Genetics and IVF Institute, Fairfax, Virginia.
Perszyk
J
J
Robinson
P
P
Black
S H
SH
Schulman
J D
JD
D000328:Adult; D000649:Amniocentesis; D015193:Chorionic Villi Sampling; D002881:Chromosomes, Human, Pair 12; D002885:Chromosomes, Human, Pair 16; D002889:Chromosomes, Human, Pair 2; D002897:Chromosomes, Human, Pair 7; D005188:False Negative Reactions; D005260:Female; D006801:Humans; D011247:Pregnancy; D011256:Pregnancy Outcome; D014314:Trisomy