[Genetic counseling in the case of carrier state with reciprocal chromosome translocations]

The principles are presented of genetic counselling for families with carrier state of reciprocal chromosome translocations (RCT). RCTs are the risk factor for the occurrence of reproduction disturbances, such as infertility, spontaneous abortion, congenital anomalies in the offsprings, and the degree of risk depends to a large extent on which chromosome segments are in the state of imbalance in the offsprings, due to various mechanisms of abnormal meiotic segregation. The uniqueness of chromosome translocations with respect to the type of chromosomes involved in translocations, and the location of breaking sites is the reason for the necessity of construing large pedigrees for the evaluation of the degree of risk. The newest Stene and Stengel-Rutkowski model makes possible the combination of smaller pedigrees in translocation groups of the so-called single risk of imbalance and determination of the individual risk of birth of children with anomalies. A number of psychological determinants are important for the possibility of genetic investigations in the affected families, and the decision about procreation may be influenced by a number of determinants other than the result of genetic counsel.