Prenatal diagnosis of trisomy 3 mosaicism.
OBJECTIVE
To present the clinical, cytogenetic, and molecular cytogenetic findings of prenatally diagnosed trisomy 3 mosaicism.


METHODS
Trisomy 3 mosaicism is rare, and only two cases of prenatally diagnosed trisomy 3 mosaicism have been reported. Amniocentesis, performed for AMA, revealed a karyotype of 47,XX, + 3[8]/46,XX[27]. Periumbilical blood sampling (PUBS) showed 46,XX in 100 cells. Fluorescence in situ hybridization (FISH) analysis using an alpha satellite chromosome 3 probe confirmed the cytogenetic findings. A repeat amniocentesis confirmed mosaicism for trisomy 3 (47,XX, + 3[1]/46,XX[18]). The infant was delivered by elective C-section because of the presence of IUGR and oligohydramnios. The baby had normal physical findings at birth except for symmetric IUGR, apparently resulting from the placental trisomic cell lines. At delivery, chromosome analysis of 50 cells each from blood, placenta, and umbilical cord revealed 46,XX in all cells. FISH analysis of amniotic fluid cells (54 nuclei), peripheral blood (50 nuclei), umbilical cord fibroblasts (57 nuclei), and placental tissue (52 nuclei) demonstrated two signals in 200 nuclei (i.e., 46,XX) and three signals in 13 nuclei (i.e., 47,XX, + 3). At 11 months of age, the baby was progressing normally.


CONCLUSIONS
A diagnosis of trisomy 3 mosaicism is problematic for patients and clinicians. This is only the third case of trisomy 3 mosaicism identified at amniocentesis. Ultrasound, PUBS, and evaluation of placental tissues and postnatal peripheral blood, were useful in providing information regarding the fetal involvement of trisomy 3. Additional cases of prenatally diagnosed mosaicism for rare trisomies are necessary to more accurately assess the significance of these findings.
Zaslav
Ann-Leslie
AL
Division of Cytogenentics, Department of Laboratory Medicine, Long Island Jewish Medical Center, The Long Island Campus of the Albert Einstein College of Medicine, New Hyde Park, New York 11040, USA. azaslav@lij.edu
Pierno
Guy
G
Davis
Jessica
J
Fougner
Arthur
A
Jacob
Jessy
J
Kazi
Rehana
R
Blumenthal
Donna
D
Sturim
Sandra
S
Shaham
Meira
M
Fox
Joyce
J
D000328:Adult; D000649:Amniocentesis; D002893:Chromosomes, Human, Pair 3; D005260:Female; D005312:Fetal Blood / Q000166:cytology; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007621:Karyotyping; D008297:Male; D009030:Mosaicism; D011247:Pregnancy; D011296:Prenatal Diagnosis; D014314:Trisomy / Q000175:diagnosis* / Q000235:genetics