Biopsy of cleavage stage human embryos and diagnosis of single gene defects by DNA amplification.

Preimplantation diagnosis offers an alternative to current prenatal diagnostic techniques for patients known to be at risk of transmitting an inherited disease. One or two cells can be removed from cleavage stage embryos from patients undergoing in vitro fertilization. Affected embryos can be identified by analyzing the cells for the defect using the polymerase chain reaction. Following analysis, embryos identified as unaffected are replaced in the patient. The identification and transfer of female embryos was attempted in eight couples known to be at risk of transmitting various X-linked diseases. Five of the eight women became pregnant, two with twin and three with singleton pregnancies, after a total of 13 treatment cycles. Six of the seven fetuses were confirmed as being female after chorionic villus sampling. The prospects for the specific diagnosis of single gene defects are described.