NORMAL-PREGNANCY AFTER PREIMPLANTATION DNA DIAGNOSIS OF A DYSTROPHIN GENE DELETION

To perform preimplantation DNA diagnosis for Duchenne muscular dystrop hy (DMD) in a female carrier of a dystrophin gene deletion of exons 3- 18, we developed a polymerase chain reaction (PCR)-based assay of exon 17 sequences. Exon 17 was efficiently amplified in all 50 single blas tomeres of normal control embryos and in five blastomeres of one male embryo of the DMD carrier obtained after a first preimplantation diagn osis (PID) for gender determination. In ten blastomeres of another two male embryos of the DMD carrier, no PCR signals were observed, probab ly as a result of the deletion. After intracytoplasmic sperm injection , embryos were analysed for exon 17 and three of the four embryos show ing normal PCR signals were replaced, resulting in a singleton pregnan cy. Prenatal diagnosis showed a female karyotype and DNA analysis indi cated that the fetus was not a DMD carrier.