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.

Preimplantation genetic diagnosis for polycystic kidney disease.

OBJECTIVE: To use preimplantation genetic diagnosis for achieving a polycystic kidney disease (PKD)-free pregnancy for a couple in which the female partner was affected by PKD but whose PKD1 or PKD2 carrier status was not established. DESIGN: Case report. SETTING: The IVF program of Reproductive Genetics Institute, Chicago, Illinois. PATIENT(S): An at-risk couple with the female partner affected by PKD, whose PKD1 or PKD2 carrier status was not established. INTERVENTION(S): Removal of PB1 and PB2 and testing for three closely linked markers to PKD1 (Kg8, D16S664, and SM7) and four closely linked markers to PKD2 (D4S2922, D4S2458, D4S423, and D4S1557) after standard IVF. MAIN OUTCOME MEASURE(S): Deoxyribonucleic acid analysis of PB1 and PB2 indicating whether corresponding oocytes were PKD1 or PKD2 allele free, for the purpose of transferring only embryos resulting from mutation-free oocytes. RESULT(S): Of 11 oocytes tested by PB1 and PB2 DNA analysis, 7 were predicted to contain PKD1 or PKD2, with the remaining 4 free of both mutations. Three embryos resulting from these oocytes were transferred, yielding a twin pregnancy and the birth of two unaffected children. CONCLUSION(S): This is the first preimplantation genetic diagnosis for PKD, which resulted in the birth of healthy twins confirmed to be free of PKD1 and PKD2. Preimplantation genetic diagnosis based on linked marker analysis provides an alternative for avoiding the pregnancy and birth of children with PKD, even in at-risk couples without exact PKD1 or PKD2 carrier information.

Preimplantation HLA typing with aneuploidy testing.

Preimplantation HLA typing has been introduced for the treatment of affected siblings, requiring HLA-identical stem cell transplantation. This was applied either in combination with preimplantation genetic diagnosis (PGD) to ensure that the preselected HLA-matched embryos were also free of the genetic disorder, or without PGD, with the only purpose of selecting and transferring the HLA-matched embryos. Because patients requesting preimplantation HLA typing are usually of advanced reproductive age, aneuploidy testing allows not only the avoidance of the birth of children with chromosomal disorders, but also improvement of the reproductive outcome, which is still not sufficiently high in preimplantation HLA typing at the present time. This study presents the results of the first experience of preimplantation HLA typing combined with aneuploidy testing, demonstrating feasibility and impact of aneuploidy testing on the accuracy and outcome of preimplantation HLA typing. Of a total of 138 cycles performed, 87 were combined with PGD and 52 without testing for the causative gene, of which aneuploidy testing was performed in 27 cycles, allowing the preselection and transfer of only those HLA-matched embryos that were also euploid. Although the euploid HLA-identical embryos were available for transfer in only half of these cycles, pregnancy and birth of unaffected HLA-identical children were observed in approximately half of these cycles, suggesting the potential usefulness of incorporating aneuploidy testing into preimplantation HLA typing.

Preimplantation genetic diagnosis for cancer predisposition.

Preimplantation genetic diagnosis (PGD) has recently been offered for couples with an inherited predisposition for late onset disorders. This paper presents the results of PGD for a group of couples at risk for producing children with cancer predisposition. Using a standard IVF procedure, oocytes or embryos were tested for different mutations predisposing to cancer, preselecting and transferring only mutation-free embryos back to the patients. The procedure was performed for patients with predisposition to familial adenomatous polyposis coli (FAP), Von Hippel-Lindau syndrome (VHL), retinoblastoma, Li-Fraumeni syndrome, determined by p53 tumour suppressor gene mutations, neurofibromatosis types I and II and familial posterior fossa brain tumour (hSNF5). Overall, 20 PGD cycles were performed for 10 couples, resulting in preselection and transfer of 40 mutation-free embryos, which resulted in five unaffected clinical pregnancies and four healthy children born by the present time. Despite the controversy of PGD use for late onset disorders, the data demonstrate the usefulness of this approach as the only acceptable option for at-risk couples to avoid the birth of children with an inherited predisposition to cancer, and to have a healthy child.