Prenatal diagnosis in 100 structural rearrangements of the chromosomes.

Among 900 couples referred for prenatal diagnosis, the indication was a parental balanced structural chromosome anomaly in 94, of which 39 were Robertsonian translocations, 38 reciprocal translocations, and 17 pericentric inversions. Six fetuses were unbalanced. The methods of ascertainment of the anomaly in these couples and the gametic segregation transmitted to the concepti are analyzed. A de novo unbalanced structural anomaly was detected in fetal cells in 6 diagnoses performed in couples referred for indications other than chromosomal.