Prenatal detection of a de novo Yqh-acrocentric translocation.
OBJECTIVE
To identify the extra chromosomal material on 46,XX,21p+ for prenatal diagnosis.


METHODS
Conventional cytogenetic studies using GTG (G bands by trypsin using Giemsa) and CBG (C bands by barium hydroxide using Giemsa) techniques were performed on chromosomes at metaphase obtained from cultured amniocytes and parental blood lymphocytes. Molecular cytogenetic techniques, QF-PCR (quantitative fluorescent polymerase chain reaction), FISH (fluorescent in-situ hybridization), and DA-DAPI (Distamycin A and 4,6-diamino-2-phenylindole) staining, were then used to clarify the extra material present on fetal chromosome 21 p.


RESULTS
The extra material on fetal chromosome 21 p has originated from Yqh, most likely at PAR2 (the secondary pseudoautosomal region). The karyotype should be 46,XX,der(21)t(Y;21)(q12;p13)de novo.ish der(21)t(Y;21)(q12;p13) (EST Cdy16c07+).


CONCLUSIONS
This case demonstrates the usefulness of molecular techniques in the investigation of rare chromosomal rearrangements.
Ng
Lucy K L
LK
Prenatal Diagnostic and Counselling Department, Tsan Yuk Hospital. Sai Ying Pun, Hong Kong SAR, China. ng_lucy59@hotmail.com
Kwok
Yvonne K
YK
Tang
Linda Y F
LY
Ng
Paulina P Y
PP
Ghosh
A
A
Lau
Elizabeth T
ET
Tang
Mary H Y
MH
D000328:Adult; D000653:Amniotic Fluid / Q000166:cytology; D002478:Cells, Cultured; D002871:Chromosome Banding; D002891:Chromosomes, Human, Pair 21 / Q000235:genetics; D041322:Chromosomes, Human, Y / Q000235:genetics; D005260:Female; D005333:Fetus / Q000378:metabolism*; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007621:Karyotyping; D008677:Metaphase / Q000235:genetics; D011247:Pregnancy; D011296:Prenatal Diagnosis; D014178:Translocation, Genetic / Q000235:genetics*