Cell recycling of a single human cell for preimplantation diagnosis of X-linked disease and dual sex determination.

We recently described a new procedure, called 'cell recycling', which combines the two powerful techniques of polymerase chain reaction (PCR) and fluorescent in-situ hybridization (FISH) on the same single fixed cell. The dual procedure was developed to single cell sensitivity using single blastomeres of preimplantation mouse embryos. We have now extended the procedure to single human cells and demonstrated its potential use in preimplantation diagnosis to detect Duchenne muscular dystrophy (DMD) by PCR, in addition to sexing the same single cell by both PCR and FISH. Here we report an efficiency of 65% for cell recycling with efficiencies for PCR ampification of a single copy DMD sequence at 87% and sexing by FISH at 75%. Should PCR diagnosis of the DMD mutation fail, cell recycling would provide two opportunities to identify the sex of the embryo, allowing selection of only the female embryos for transfer.