Co-Amplification of X- and Y-Specific Sequences for Sexing Preimplantation Human Embryos

Abstract

For couples at risk of X-linked recessive diseases, which typically affect only males, in vitro fertilization followed by the identification and transfer of female preimplantation embryos provides an alternative to prenatal diagnosis at later stages of pregnancy and the possibility of terminating an affected pregnancy. DNA amplification of a Y chromosome-specific repeat sequence by the polymerase chain reaction (PCR) from single cells biopsied at the 6- to 10-cell stage allows the identification of male, and absence of amplification, female embryos, within a few hours (Handyside et al., 1989). Several pregnancies have now been established using this approach with these couples (Handyside et al., 1990; Handyside, this volume) and, to date, all five fetuses in two sets of twins and a singleton pregnancy have been confirmed, by chorion villus sampling and cytogenetic analysis, to have normal female karyotypes.