Pre-implantation genetic diagnosis (PGD) offers high-risk couples for genetic diseases in their offspring the option of detecting these diseases before implantation of the embryos. By analyzing the polar bodies (PBs) manipu­lation of the embryo itself is avoided [1].

This is also the only possibility of performing PGD in Germany due to the “Embryo Protection Law” (Embryo­nenschutzgesetz) [2,3]. Termination of pregnancy after prenatal diagnosis is accepted and practised in Germany. However, some couples refuse pregnancy interruption so that PB diagnosis is considered as an alternative. The limitation of PB diagnosis is that one can only test one cell and analyze only the maternal genome.

Cystic fibrosis (CF) is the most common severe auto­somal recessive disease in the Caucasian population, af­fecting about 1 in 2,500 newborns. The most predominant defect, accounting for 70-75% of all CF mutations in North Europe, is a 3 bp deletion at amino acid position 508 (DF508). At the present time, more than 900 different mutations in the CF transmembrane conductance regulator gene (CFTR) have been reported. To make pre-implanta­tion diagnosis reliable for affected couples and compatible with the restrictions by the German law, we established a multiplex polymerase chain reaction (PCR) assay for PB testing.

Chromosomal aneuploidy is the most frequent cause for loss of pregnancies [4]. Early pregnancy losses, without the possibility of analyzing the embryonal karyotype, may also be caused, to a considerable degree, by aneuploidy. By fluorescent in situ hybridization (FISH) using specific fluorochrome-labelled DNA probes for different chromo­somes, it is possible to evaluate the number of the marked chromosomes in interphase cells. Fluorescent in situ hy­bridization was used for the first time to detect sex chro­mosomes in human blastomeres [5]. This technique was expanded to detect aneuploidies for three or more chromo­somes in blastomeres and also in PBs [6,7]. We present our first data after first PB diagnosis for aneuploidies of chromosomes 15, 16 and 22.