Differences in chromosome susceptibility to aneuploidy and survival to first trimester.
The purpose of this study was to find specific rates of aneuploidy in cleavage-stage embryos compared with first trimester data and to evaluate post-zygotic selection against aneuploidy. A total of 2058 embryos were analysed by flurorescence in-situ hybridization (FISH), and specific aneuploidy rates were obtained for 14 chromosomes. Data from morphologically abnormal embryos could be pooled with data from preimplantation genetic diagnosis (PGD) cycles because it was observed that they had similar rates of aneuploidy; thus, for the purpose of studying aneuploidy they could be, and were, pooled. Specific chromosome aneuploidy rates were not related to morphology or development of the embryos. The average maternal age of patients with aneuploid embryos was significantly higher than the overall analysed population. Monosomy appeared more commonly than trisomy. The chromosomes most frequently involved in aneuploidy were (in order) 22, 16, 21 and 15. When compared with first trimester pregnancy data, aneuploidies detected at cleavage stage seem to die in excess of 90% before reaching first trimester, with the exception of chromosome 16 and gonosomes (76% and 14% respectively). Differences in chromosome-specific aneuploidy rates at first trimester conceptions are probably produced by different chromosome-specific aneuploidy rates at cleavage stage and different survival rates to first trimester.
Munné
Santiago
S
Institute for Reproductive Medicine and Science, Saint Barnabas Medical Center, Livingston, New Jersey, USA. santi.munne@embryos.net
Bahçe
Muhterem
M
Sandalinas
Mireia
M
Escudero
Tomás
T
Márquez
Carmen
C
Velilla
Esther
E
Colls
Pere
P
Oter
Maria
M
Alikani
Mina
M
Cohen
Jacques
J
D000782:Aneuploidy; D002877:Chromosomes, Human / Q000235:genetics*; D002884:Chromosomes, Human, Pair 15 / Q000235:genetics; D002885:Chromosomes, Human, Pair 16 / Q000235:genetics; D002891:Chromosomes, Human, Pair 21 / Q000235:genetics; D002892:Chromosomes, Human, Pair 22 / Q000235:genetics; D002970:Cleavage Stage, Ovum / Q000502:physiology; D004622:Embryo, Mammalian / Q000002:abnormalities; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D008423:Maternal Age; D009006:Monosomy; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D019836:Preimplantation Diagnosis; D013534:Survival; D014314:Trisomy