Amniotic trisomy 11 mosaicism--is it a benign finding?
OBJECTIVE
A case of prenatally diagnosed trisomy 11 mosaicism with a normal outcome is reported and the medical literature on prenatal detection of this finding is reviewed.


METHODS
Proportion of cells with trisomy 11 was evaluated in amniocytes, fetal blood lymphocytes, newborn fibroblasts and urinary epithelial cells. Karyotype studies and fluorescence in situ hybridization analysis using the 11q13LS1 CCND1 probe were performed.


RESULTS
Trisomy 11 level III mosaicism of 26% was detected in amniotic fluid cells. Periumbilical blood sampling showed a normal fetal karyotype. No fetal structural abnormalities were noted on ultrasound scan. The infant was spontaneously delivered and had normal physical findings at birth. No evidence of trisomic cells was found on extensive postnatal evaluation, implying an extraembryonic origin. Molecular analysis excluded uniparental disomy of chromosome 11. At 1 year of age, the baby is developing normally.


CONCLUSIONS
Only three reports on trisomy 11 mosaicism identified at amniocentesis have been published previously, all with a normal outcome. Additional cases of prenatally diagnosed mosaicism for trisomy 11 are necessary to assess more accurately the clinical significance of this finding.
Basel-Vanagaite
Lina
L
Department of Medical Genetics, Rabin Medical Center, Beilinson Campus, Petah Tiqva, Israel. basel@post.tau.ac.il
Davidov
Bella
B
Friedman
Jane
J
Yeshaya
Yosefa
Y
Magal
Nurit
N
Drasinover
Valerie
V
Shohat
Mordechai
M
D000328:Adult; D000649:Amniocentesis; D002880:Chromosomes, Human, Pair 11; D005260:Female; D006801:Humans; D008297:Male; D009030:Mosaicism; D011247:Pregnancy; D011379:Prognosis; D014314:Trisomy / Q000175:diagnosis*