Elucidation of abnormal fertilization by single-cell analysis with fluorescence in situ hybridization and polymorphic marker analysis.
OBJECTIVE
To analyze the genetic composition of oocytes and embryos presenting abnormal fertilization.


METHODS
Case report.


METHODS
In vitro fertilization unit of a university-affiliated hospital.


METHODS
A couple with unexplained infertility with abnormal fertilizations in nine failed IVF-intracytoplasmic sperm injection cycles characterized by the presence of embryos with only one pronucleus and nonextrusion of the second polar body.


METHODS
All first polar bodies and blastomeres were analyzed by fluorescence in situ hybridization for chromosomes 13, 18, 21, X, and Y. Because some of the one-pronucleus embryos were found to be diploid, they were subjected further to single-cell polymerase chain reaction analysis with use of a panel of highly polymorphic markers from chromosomes 6, 7, 17, 19, X, and Y.


METHODS
Fluorescence in situ hybridization analysis of polar bodies and blastomeres and polymorphic marker analysis of day 5 embryos.


RESULTS
Fluorescence in situ hybridization analysis of the first polar body demonstrated normal segregation of chromosomes in meiosis I. Fluorescence in situ hybridization analysis of two aspirated blastomeres demonstrated three diploid and two mosaic triploid embryos. Polymorphic marker analysis, however, demonstrated that all embryos, including the diploid ones, had two sets of maternal alleles.


CONCLUSIONS
Single-cell genetic analysis routinely used for preimplantation genetic diagnosis may provide insight into the genetic composition of oocytes and embryos. These data may be used in cases of abnormal fertilization or impaired embryo development for evidence-based fertility counseling regarding prognosis and treatment options.
Malcov
Mira
M
Racine IVF Unit, Lis Maternity Hospital, Tel Aviv Sourasky Medical Center, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
Frumkin
Tsvia
T
Shwartz
Tamar
T
Azem
Foad
F
Amit
Ami
A
Yaron
Yuval
Y
Ben-Yosef
Dalit
D
D001757:Blastomeres / Q000473:pathology*; D002869:Chromosome Aberrations; D020090:Chromosome Segregation; D047108:Embryonic Development / Q000235:genetics; D005260:Female; D005307:Fertilization in Vitro; D005819:Genetic Markers; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007246:Infertility / Q000235:genetics / Q000628:therapy*; D008297:Male; D008540:Meiosis / Q000235:genetics; D009865:Oocytes / Q000473:pathology*; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D019836:Preimplantation Diagnosis / Q000379:methods*; D020554:Sperm Injections, Intracytoplasmic; D017211:Treatment Failure
D005819:Genetic Markers