Example of the strategy used for PGD of myotonic dystrophy

For myotonic dystrophy, characterized by the presence of a dynamic mutation involving the expansion of a trinucleotide repeat sequence, a multiplex fluorescent PCR protocol was used. Since the large expanded alleles are refractive to PCR amplification, a general approach, allowing detection of only healthy alleles, was applied. The PGD strategy involved amplification of the DNA fragment around the repeated region and STR markers linked to this region for ADO detection (Sermon et al., 1998; Dean et al., 2001).