Lack of aneuploidy for chromosomes 15, 16, and 18 in placentas from small-for-gestational-age liveborn infants.
OBJECTIVE
The purpose of this study was to investigate the frequency of confined placental mosaicism (CPM) in placentas from liveborn infants.


METHODS
A retrospective analysis of 51 placentas from small-for-gestational-age (SGA), live born infants (birthweight below 5th centile), and 45 placentas from normally grown infants at term was performed. Aneuploidy for chromosomes 15, 16, and 18 was analyzed with QF-PCR (polymorphic markers) and FISH (centromeric probes).


RESULTS
No trisomic sample was detected with either method. FISH revealed 1 case of monosomy 16 in the SGA group, which was not confirmed by PCR. On the other hand, PCR analysis showed allelic imbalances, ie, deviation of the 1:1 peak ratio > 20%, in 5 cases (4 in the SGA and 1 in the control group; P = .157).


CONCLUSIONS
Trisomic CPM in liveborn SGA infants is much less frequent than previously appreciated. The occurrence and eventual biologic significance of the observed allelic imbalances needs to be further investigated.
Papadogiannakis
Nikos
N
Department of Pathology, Karolinska Institutet, Stockholm, Sweden. nikos.papadogiannakis@ki.se
Iwarsson
Erik
E
Taimi
Teija
T
Zaphiropoulos
Peter G
PG
Westgren
Magnus
M
D000328:Adult; D000782:Aneuploidy; D016022:Case-Control Studies; D002877:Chromosomes, Human / Q000235:genetics*; D002884:Chromosomes, Human, Pair 15 / Q000235:genetics; D002885:Chromosomes, Human, Pair 16 / Q000235:genetics; D002887:Chromosomes, Human, Pair 18 / Q000235:genetics; D005260:Female; D005317:Fetal Growth Retardation; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007231:Infant, Newborn; D007236:Infant, Small for Gestational Age; D010920:Placenta / Q000737:chemistry*; D016133:Polymerase Chain Reaction; D011247:Pregnancy; D012189:Retrospective Studies