Preimplantation genetic diagnosis for the Kell genotype.

Objective: To use preimplantation genetic diagnosis (PGD) to achieve a Kell 1 (K1) allele-free pregnancy in couples at risk for producing a child with hemolytic disease of the newborn (HDN) caused by maternofetal incompatibility in sensitized mothers.

Design: DNA analysis of biopsied blastomeres from cleavage-stage embryos in IVF-ET with the goal of identifying and transferring back to patients the K1 allele-free embryos.

Setting: IVF program at the Reproductive Genetics Institute, Chicago, Illinois, and IVF Michigan, Rochester Hills, Michigan.

Patient(s): Two at-risk couples with a history of neonatal death caused by HDN due to K1/K2 genotype in a male partner.

Intervention(s): Biopsy of single blastomeres and testing for paternal K1 allele in each embryo after standard IVF.

Main Outcome Measure(s): DNA analysis of blastomeres indicating whether corresponding embryos were K1 allele-free for the purpose of transferring only embryos without the K1 allele.

Result(s): Of 36 embryos tested in five cycles from two couples, 18 were predicted to be K1 allele-free. Of these, 9 were transferred, resulting in a K1 allele-free twin pregnancy and the birth of two healthy children.

Conclusion(s): PGD of the K1 genotype resulted in the birth of healthy twins confirmed to be free of the K1 allele. PGD in couples with a heterozygous K1/K2 male partner provides an option for avoiding HDN in sensitized mothers.