Experience of Preimplantation Genetic Diagnosis for Hemophilia at the University Hospital Virgen Del Rocío in Spain: Technical and Clinical Overview

Abstract

Hemophilia A and B are the most common hereditary hemorrhagic disorders, with an X-linked mode of inheritance. Reproductive options for the families affected with hemophilia, aiming at the prevention of the birth of children with severe coagulation disorders, include preimplantation genetic diagnosis (PGD). Here we present the results of our PGD Program applied to hemophilia, at the Department of Genetics, Reproduction and Fetal Medicine of the University Hospital Virgen del Rocío in Seville. A total of 34 couples have been included in our program since 2005 (30 for hemophilia A and 4 for hemophilia B). Overall, 60 cycles were performed, providing a total of 508 embryos. The overall percentage of transfers per cycle was 81.7% and the live birth rate per cycle ranged from 10.3 to 24.1% depending on the methodological approach applied. Although PGD for hemophilia can be focused on gender selection of female embryos, our results demonstrate that methodological approaches that allow the diagnosis of the hemophilia status of every embryo have notorious advantages. Our PGD Program resulted in the birth of 12 healthy babies for 10 out of the 34 couples (29.4%), constituting a relevant achievement for the Spanish Public Health System within the field of haematological disorders.

Single‐tube tetradecaplex panel of highly polymorphic microsatellite markers < 1 Mb from F8 for simplified preimplantation genetic diagnosis of hemophilia A

“…Compared with a previously reported hexaplex panel where two out of four extragenic markers are >1 Mb from the F8 gene , all extragenic markers in our panel locate within 0.6 Mb from the F8 gene, thus minimizing misdiagnosis or no diagnosis caused by recombination between the markers and the F8 gene. Using this newly developed panel, the percentage of individuals harboring at least one heterozygous intragenic marker (~80%) and one heterozygous extragenic marker on each side of the F8 gene (~98%) was higher compared with another hexaplex panel (~70% and ~86%, respectively) in the Chinese population .…”

“…Therefore, this new panel improves the odds of identifying markers that are informative for use in standalone indirect linkage analysis, or as a complement to direct mutation detection, in couples wishing to undergo PGD for HEMA. Several reports have demonstrated that multiplex marker PCR is a reliable indirect linkage-based PGD method for cases involving inversion mutations [19][20][21][22]. Hence, this tetradecaplex marker panel, which contains more markers than previously reported panels, is likely to benefit carriers of the intron-1 or intron-22-mediated inversion mutations the most, because direct single-cell mutation detection is not possible and indirect linkage analysis is the only option [19].…”

“…Microsatellite markers, also referred to as short tandem repeats (STRs), have been widely used in linkage analysis as they are highly polymorphic and widespread within the human genome. A list of STRs located in and around the F8 gene has been reported previously [10], some of which have been multiplexed in small panels [9,[11][12][13][14][15][16][17][18][19][20][21][22]. However, a majority of these STRs have not been tested experimentally and their heterozygosity and polymorphism indices are unknown.…”

Establishing a comprehensive genetic diagnosis strategy for hemophilia B and its application in Chinese population

“…8 Most patients with HB can be detected by direct DNA sequencing. Moreover, we noticed that some clinics still offered PGD for HB families by gender selection, and transfer of only female embryos 13 and few researches about PGD of HB has been reported. 9 Preimplantation genetic diagnosis cycle which is an advanced assisted conception technique that gives couples the chance of giving birth to an unaffected child of a specific disease is regarded as a better option since possible termination of an affected pregnancy after prenatal diagnosis frequently confronts to the religious, ethics, and culture.…”

Management of Inherited Bleeding Disorders in Pregnancy

“…Success rates of around 30% have been reported. 31 Carriers of male fetuses confirmed to be affected by severe haemophilia should be counselled to enable informed choices. 32 Evidence level 4…”