Meiotic behavior of three D;G Robertsonian translocations: segregation and interchromosomal effect.

Robertsonian translocations are one of the most frequent reorganizations in humans. Their segregational behavior and their implication in the occurrence of interchromosomal effects (ICEs) has been an important topic of research for the past 10 years. Most of the cases analyzed correspond to rearrangements with chromosomes from the D-group (chromosomes 13, 14 and 15), whereas some rare Robertsonian translocations are scarcely found in the literature, mainly those with both chromosomes from the G-group (chromosomes 21 and 22) and those involving chromosomes from both groups (D;G translocations). Results supporting/rejecting the existence of the ICE phenomenon have been reported, showing the need for more studies to characterize its distribution. In this study, sperm fluorescent in situ hybridization studies have been performed in three D;G Robertsonian translocation carriers: two men with the translocation t(14;21) and a third individual with the rare t(13;22) reorganization. Segregation and ICE results have been considered in relation to their cytogenetic features and all previously published data. The compiled information discards a particular segregation behavior related to the chromosomes involved. In contrast with this segregational homogeneity, heterogeneous ICE results were observed, indicating a significant but random distribution of such phenomenon.