Variable outcomes in mosaic trisomy 16: five case reports and literature analysis.
OBJECTIVE
To report five cases of mosaic trisomy 16 with variable outcomes in the context of the literature on mosaic trisomy 16. Complications in these cases include preeclampsia, IUGR, fetal anomalies, and death, with no predictable pattern.


METHODS
Observation of five new cases and statistical analysis of 125 reported cases of mosaic trisomy 16 with prenatal detection and outcome data.


RESULTS
(1) IUGR, premature delivery, and/or physical anomalies are observed commonly, even when the trisomy is thought to be confined to the placenta; (2) Level II mosaicism for trisomy 16 in amniotic fluid may reflect a true mosaic state with phenotypic consequences; (3) FISH is more sensitive than traditional cytogenetics in detecting mosaicism in all tissue types examined; (4) hCG levels can be extremely elevated, and MS-AFP levels are often elevated; and (5) Uniparental disomy (UPD) increases the rates of IUGR and physical anomalies in CPM cases.


CONCLUSIONS
While there is no obvious mosaic trisomy 16 syndrome, IUGR and heart defects commonly occur, even if the mosaicism appears to be confined to the placenta. A completely normal outcome occurs only in about 20% of the cases; however, complications can often be limited to prematurity, small-for-gestational-age infants, and/or minor or surgically reparable birth defects.
Neiswanger
Katherine
K
School of Dental Medicine, University of Pittsburgh, Pittsburgh, PA 15213, USA.
Hohler
Paul M
PM
Hively-Thomas
Lori B
LB
McPherson
Elizabeth W
EW
Hogge
W Allen
WA
Surti
Urvashi
U
D000328:Adult; D002885:Chromosomes, Human, Pair 16; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D009030:Mosaicism; D011247:Pregnancy; D011256:Pregnancy Outcome / Q000235:genetics*; D011379:Prognosis; D014314:Trisomy