ABSTRACT
Polar body (PB) biopsy dates back to the 1990s when the technique was introduced by Verlinsky et al. [1] to diagnose chromosomal abnormalities. In contrast to preimplantation genetic diagnosis (PGD) of the embryo that was proposed earlier by Alan Handyside et al. [2], PB biopsy enabled a genetic diagnosis before the formation of the proper embryo, thereby establishing the term “preconception genetic diagnosis.” PBs are by-products of the meiotic division. The rst PB (PB1) is not required for successful fertilization or for normal embryonic development. The second PB (PB2), extruded from the oocyte after initiation of the fertilization cascade by the spermatozoa, is similarly not needed for subsequent embryo development. Furthermore, it is important to note that PB diagnosis gives direct information about the rst and second PBs and therefore allows only an indirect diagnosis of the maternal genetic or chromosomal constitution of the corresponding oocyte. In contrast, analysis of blastomeres from the embryo gives a direct diagnosis for the embryo and allows for detection of both maternally and paternally derived genetic or chromosomal contributions.
