Higher than expected reproductive risk for autosomal paracentric inversion carriers

Introduction: Autosomal paracentric inversions are generally considered to be harmless without phenotypic effect in carriers, but recombination can occur during gametogenesis causing genetically unbalanced gametes and embryos. If a recombinant gamete is formed following a crossover in the inverted segment, the chromosome would be either acentric or dicentric. The resulting embryo will be unbalanced. This could lead to repeated IVF failures or repeated pregnancy loss, frequently seen among inversion carriers as well as a possible affected child. Previous studies performed in sperm of autosomal paracentric inversion carriers show recombination is scarcely ever seen (0–0.81% of recombinants in 5 cases) with the exception of one sperm FISH study showing 28% of recombinant gametes. The main goal of this study is to retrospective analyze the results of PGD performed in autosomal paracentric inversion carriers, in order to see the number and frequency of unbalanced embryos and its possible relationship with the inversion size.