Is there a correlation between the proportion of cells with isodicentric Yp at amniocentesis and phenotypic sex?
OBJECTIVE
(1) To present a case with prenatally detected idic Yp. (2) To review literature to assess if there is a correlation between the proportion of amniocytes with idic Yp and phenotypic sex.


METHODS
Seventeen cases were reviewed.


RESULTS
Amniocentesis was done due to positive integrated prenatal screening result. Interphase FISH was normal for chromosomes 13, 18, and 21, but mosaic for cell lines with 1 X and 0 to 2 copies of DYZ3, SRY, or DYZ1(Yq12). Amniocytes had 45,X[28]/46,X,idic(Y)(q11.2)[2].ish idic(Y)(DYZ3 + +, SRY + +). An apparently normal female was born at 37 weeks. The umbilical cord had 45,X[50], but cord blood had 45,X[17]/46,X,idic(Y)[31]/47,X,idic(Y)x2[2]. Review of 17 cases showed that 13 cases with 20 to 100% cells with idic Yp all had a male phenotype. Two cases with 3 and 7% of idic Yp cells had a female phenotype. Two cases with 45,X only at prenatal diagnosis but idic Yp detected postnatally were phenotypic male.


CONCLUSIONS
(1) We present the first report of prenatally detected idic Yp and Yq12 resulting in an apparently normal female at birth. (2) Finding of > 20% of G-banded amniocytes with idic Yp in the absence of other indicators of foetal structural anomalies seems to correlate with phenotypically normal male in most cases.
Xu
Jie
J
Cytogenetics, London Health Sciences Centre, University of Western Ontario, London, Ontario, Canada. Jie.Xu@lhsc.on.ca
Siu
V M
VM
D000328:Adult; D000649:Amniocentesis; D041322:Chromosomes, Human, Y; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D009030:Mosaicism; D010375:Pedigree; D011247:Pregnancy; D012723:Sex; D012729:Sex Chromosome Aberrations