Results of preimplantation screening offer new hope for treatment of recurrent miscarriage.
Preliminary study published in Human Reproduction reports over 70% clinical pregnancy rate in previously challenging cohort.
A new publication by Francesco Fiorentino1 at Genoma in Rome presents the first results of a preimplantation genetic screening study in cases of recurrent miscarriage arising from balanced translocations in one or both parents. Balanced translocations are carried by up to 1 in 500 of the general population. In such cases the carrier parent is typically unaffected however the underlying genetic aberrations can result in embryos with large structural imbalances which are seldom viable and frequently end in miscarriage.
The team at Genoma used BlueGnome’s 24sure+ platform to screen 228 embryos from 28 affected couples undergoing IVF treatment. The paper reports that 24sure+ gave results on 93% of the samples tested but that only 16% of these were genetically normal. As a result viable embryos were identified in over 60% of the couples. Most encouraging, over 70% of the embryos transferred in these cases went on to form successful pregnancies, more than double the rate that was reported using earlier, FISH based, techniques.
Commenting on the paper Dr Dagan Wells of Oxford University, who uses the same 24sure+ platform at Reprogenetics UK, said, “Our intuition has always been that the underlying fertility of couples with balanced translocations should be very good and that if we could reliably identify and transfer a normal embryo we could expect a very good outcome. The results from Genoma in Rome are consistent with this hypothesis and indeed our own experience at Reprogenetics”.
In addition to significant improvements in outcome the paper also reported that in this cohort, (mean maternal age of 37) over a quarter of the embryos were unaffected by imbalances inherited from the parents but were carrying whole chromosome imbalances more likely to be associated with high maternal age. The importance of this finding was stressed by the paper’s author Dr Francesco Fiorentino of Genoma. “We now appreciate the there is a real benefit in screening all chromosomes in these cases, something that is very straightforward with an approach like 24sure+”.
1 Fiorentino et al. Hum Reprod. 2011 Vol.26, No.7 pp. 1925–1935