Evaluation of Risk Factors for the Birth of Children with Chromosomal Imbalance in Carriers of Autosomal Reciprocal Translocations

Resumo

An important problem of genetic counseling is to determine the personalized risk of the birth of a child with an unbalanced karyotype in families with reciprocal translocation carriers. The risks of the formation of zygotes with chromosomal imbalance among carriers of balanced autosomal translocations vary significantly. These risks will depend on the most probable type of malsegregation for each specific translocation, leading to the formation of unbalanced gametes, and the probable viability of zygotes, embryos, fetuses, or newborns with unbalanced karyotype. In turn, these probabilities depend on many factors, including cytogenetic and quantitative characteristics of the translocation. During regression analysis of several independent factors and characteristics affecting the segregation behavior of the quadrivalent in meiosis I from 49 autosomal reciprocal translocations, it was found that the terminal location of breakpoints on the chromosomes involved in the translocation is statistically significant, i.e., independently associated with the risk of the birth of a viable child with chromosomal imbalance.