Hehr A et al. | ||
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Polar Body Diagnosis for Monogenic Disorders in Regensburg Journal für Reproduktionsmedizin und Endokrinologie - Journal of Reproductive Medicine and Endocrinology 2009; 6 (1): 27-31 Volltext (PDF) Summary Praxisrelevanz Abbildungen
Keywords: Humangenetik, Preimplantationsgenetik, ICSI, monogenic disorder, PBD, PCR, PGD, PND, polar body diagnosis, polymorphic markers, preimplantation genetic diagnosis, prenatal diagnosis Polar body diagnosis (PBD) is currently the only legal option to perform a preimplantation genetic diagnosis (PGD) in Germany. The results of PBD for monogenic disorders performed at our center in Regensburg since 2001 are reported. Our data show that PBD can be safely performed on first and second polar bodies within the tight timeframe provided by the German Embryo Protection Act. It requires extensive interdisciplinary counseling of the couple, good and close cooperation between the IVF center and the genetics laboratory as well as meticulous development, validation, and performance of the individual genetic assay. Provided that these prerequisites are met, PBD can today be an acceptable option for German couples at high risk for a particular monogenic disorder in their offspring. Main arguments pro PBD usually include a decline of both conventional prenatal diagnosis and subsequently induced abortion of an affected offspring as well as the birth of an affected child. Major disadvantages of PBD in this situation include the requirement of assisted reproduction for couples in the absence of any obvious fertility problems with their immanent obstacles like pregnancy rate, remaining recurrence risk for the particular monogenic disorder, costs etc. Furthermore, PBD can only be offered for mutations, which are passed on by the female partner with her nuclear DNA (autosomal dominant, X-chromosomal as well as autosomal recessive traits). For heterozygous female mutation carriers of autosomal recessive or X-chromosomal inherited disorders PBD requires discarding all oocytes carrying the mutation, although they may result in healthy offspring if the sperm does not carry the mutation or the Y chromosome, respectively. Finally, both PBD as well as PGD can substantially reduce the recurrence risk for a particular monogenic disorder but not diminish it entirely. Therefore, conventional prenatal diagnosis (PND) should still be offered and in fact has been applied in three of seven pregnancies achieved at our center. |