A simplified and efficient method for obtaining metaphase chromosomes from individual human blastomeres.
OBJECTIVE
To develop a reliable and cost-effective technique for karyotyping single human blastomeres for preimplantation diagnosis of chromosomal translocations.


METHODS
Controlled laboratory study.


METHODS
Preimplantation genetic diagnosis and IVF program, Reproductive Genetics Institute/IVF Illinois, Chicago, Illinois.


METHODS
Patients undergoing IVF and preimplantation genetic diagnosis.


METHODS
Individual human blastomeres were fused with enucleated or intact mouse zygotes. After blastomere-cytoplast fusion, heterokaryons were fixed at metaphase of the first cleavage division or treated with okadaic acid to induce premature chromosome condensation.


METHODS
Percentage of analyzable metaphase plates and ease and reliability of the procedure.


RESULTS
The effectiveness of the proposed technique with blastomeres from day 3 diploid embryos was 91%. Sixty-three metaphases were obtained from 69 blastomeres; 3 blastomeres had not fused, 1 heterokaryon had no chromatin (an anucleated cytoplasmic bleb was biopsied and fused), and 2 heterokaryons cleaved before they were fixed.


CONCLUSIONS
Human blastomere fusion with an intact mouse zygote is an efficient and technically undemanding method for obtaining metaphase chromosome plates from individual human blastomeres for preimplantation testing for chromosomal translocations and aneuploidy.
Verlinsky
Y
Y
Reproductive Genetics Institute, Chicago, Illinois 60657, USA.
Evsikov
S
S
D000818:Animals; D001757:Blastomeres / Q000502:physiology*; D002875:Chromosomes; D003362:Cost-Benefit Analysis; D015925:Cryopreservation; D006801:Humans; D007621:Karyotyping; D008677:Metaphase / Q000502:physiology*; D051379:Mice