Polymerase chain reaction-based detection of chromosomal imbalances on embryos: the evolution of preimplantation genetic diagnosis for chromosomal translocations.
OBJECTIVE
To develop and assess a polymerase chain reaction (PCR)-based preimplantation genetic diagnosis (PGD) approach for detection of chromosomal imbalances in embryos.


METHODS
A prospective study of embryos derived from chromosome translocation carriers that have undergone PGD using a novel molecular-based approach.


METHODS
A reference molecular genetics laboratory specialized in the provision of transport PGD services and a private IVF clinic.


METHODS
Twenty-seven couples carrying 12 different reciprocal translocations and 2 Robertsonian translocations.


METHODS
Preimplantation genetic diagnosis from chromosome translocation carriers on blastomeres biopsied from cleavage stage embryos.


METHODS
Embryo diagnosis rate, pregnancy rate (PR), implantation rate, take-home-baby rate.


RESULTS
Overall, 241/251 (96.0%) embryos were successfully diagnosed for chromosome rearrangements. Preimplantation genetic screening was included in the protocol of 12 couples, involving analysis of 90 embryos, 84 (93.3%) of which were successfully diagnosed and 53 (63.1%) showed aneuploidies. Embryos suitable for transfer were identified in 24 cycles. Eighteen couples achieved a clinical pregnancy (75.0% PR/embryo transfer), with a total of 31 embryos implanted (59.6% implantation rate). Ten patients (1 triplet, 1 twin, and 8 singleton pregnancies) have delivered 13 healthy babies, and the other patients (3 twins and 5 singletons) have currently ongoing pregnancies.


CONCLUSIONS
The PCR-based PGD protocol for translocations has the potential to overcome several inherent limitations of fluorescence in situ hybridization-based tests, providing potential improvements in terms of test performance, automation, turnaround time, sensitivity, and reliability.
Fiorentino
Francesco
F
"GENOMA," Molecular Genetics Laboratory, Rome, Italy. fiorentino@laboratoriogenoma.it
Kokkali
Georgia
G
Biricik
Anil
A
Stavrou
Dimitri
D
Ismailoglu
Bahar
B
De Palma
Rosangela
R
Arizzi
Lucia
L
Harton
Gary
G
Sessa
Mariateresa
M
Pantos
Kostantinos
K
D000328:Adult; D001755:Blastocyst / Q000166:cytology / Q000378:metabolism*; D002869:Chromosome Aberrations / Q000196:embryology; D020732:Cytogenetic Analysis / Q000379:methods / Q000639:trends; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008423:Maternal Age; D008875:Middle Aged; D016133:Polymerase Chain Reaction / Q000379:methods*; D011247:Pregnancy; D019836:Preimplantation Diagnosis / Q000379:methods / Q000639:trends*; D014178:Translocation, Genetic