The experience of two European preimplantation genetic diagnosis centres on human leukocyte antigen typing.

BACKGROUND Two European centres report on human leukocyte antigen (HLA) typing of preimplantation embryos for haematopoietic stem cell (HSC) transplantation: 'UZ Brussel' in Brussels and 'Genoma' in Rome. Both centres have 6 years' experience with technical and clinical aspects of this type of genetic analysis on single blastomeres. METHODS Both centres apply a similar technique for preimplantation HLA typing using short tandem repeats linked to the HLA locus in multiplex PCR for haplotyping. RESULTS At present, a conclusive HLA diagnosis could be assured in 92.8% and 90.3% of the embryos at UZ Brussel and at Genoma, respectively. The implantation rates were 32.4% and 28.2%, respectively, and the birth rates per cycle were 9.4% and 18.6%, respectively. The HLA programme at UZ Brussel and at Genoma resulted in the birth of 9 babies and 3 successful HSC transplantations, and 42 babies and 7 successful HSC transplantations, respectively, so far. CONCLUSIONS Drastic embryo selection for preimplantation HLA typing (in theory 1/4 for HLA, 1/8 for HLA in combination with sexing for X-linked recessive diseases, 3/16 for HLA in combination with autosomal recessive disorders) resulted overall in the birth of 51 babies (15.9% live birth rate per started cycle) in two European centres.