Preimplantation diagnosis of autosomal dominant retinitis pigmentosum using two simultaneous single cell assays for a point mutation in the rhodopsin gene.

A couple requested preimplantation genetic analysis for a dominant form of retinitis pigmentosum caused by a C-->A transversion in the rhodopsin gene. Since this point mutation does not alter a restriction endonuclease site we designed two separate analytical systems, one involving site-specific mutagenesis and the other involving allele-dependent length polymorphism. After establishing the accuracy and robustness of these assay systems we utilized both systems simultaneously in a heminested polymerase chain reaction (PCR) system. This allowed accurate preimplantation diagnosis to be performed. One embryo was transferred but a pregnancy did not occur.