Demonstration of a mechanism of aneuploidy in human oocytes using Multifluor fluorescence in situ hybridization.
OBJECTIVE
To evaluate the potential of Multifluor fluorescence in situ hybridization (M-FISH) for karyotyping the human oocyte and first polar body.


METHODS
Prospective case study.


METHODS
Research laboratories, university hospital.


METHODS
A 33-year-old woman with polycystic ovary syndrome who was undergoing ovarian stimulation and ICSI.


METHODS
Karyotyping of all chromosomes within an oocyte and first polar body, using GV stage oocytes matured to metaphase II in vitro.


RESULTS
Oocyte hyperploidy was diagnosed by M-FISH to be 23, X +15 cht +19 cht +22 cht. The correspond- ing polar body was hypoploid, with a karyotype of 23, X -15 cht -19 cht -22 cht. This was due to unbalanced predivision at meiosis I. Reprobing confirmed karyotype assignments for chromosomes X, 13, 18, and 21.


CONCLUSIONS
The mechanism involved in maternally derived aneuploidy can be defined by using M-FISH to simultaneously karyotype both oocyte and first polar body chromosomes at metaphase II. Multifluor FISH may be useful for investigative studies of maternally derived aneuploidy, which is a major cause of preimplantation waste in natural and assisted reproduction.
Clyde
J M
JM
Reproductive Biology Group, Academic Unit of Paediatrics, Obstetrics and Gynaecology, University of Leeds, Leeds, United Kingdom.
Gosden
R G
RG
Rutherford
A J
AJ
Picton
H M
HM
D000328:Adult; D000782:Aneuploidy; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007621:Karyotyping; D009865:Oocytes / Q000502:physiology*; D011446:Prospective Studies