Fluorescence in situ hybridization analysis of human oocytes: Advantages of a double-labeling procedure

Objective

To improve the fluorescence in situ hybridization (FISH) chromosomal analysis of human oocytes and first polar bodies.

Design

In situ chromosomal identification on isolated cells, with combinations of centromeric (or locus-specific) probes and whole-chromosome painting probes for chromosomes 9, 13, 16, 18, 21, and X.

Setting

Montpellier University Hospital.

Patient(s)

Women participating in an IVF program.

Intervention(s)

Fifty-four in vitro unfertilized oocytes were fixed on slides, and simple or double FISH labeling procedures were performed on preparations.

Main outcome measure(s)

Simultaneous in situ visualization of specific domains and chromosome arms of each targeted chromosome.

Result(s)

Eight chromosomal abnormalities were identified, including two hyperhaploidies, three cases of extra single chromatid, and three cases of balanced separation of sister chromatids. Also, the double-labeling procedure allowed the avoidance of five interpretation errors, owing to additional artefactual signals.

Conclusion(s)

By ensuring precise identification of both chromosomes and single chromatids, the FISH double-labeling procedure limits the risk of erroneous interpretation and allows a more accurate cytogenetic analysis of human oocytes.

Key words:  FISH , human oocyte , double labeling , aneuploidy , interpretation mistakes