Experiences with unexpected structural chromosome aberrations in prenatal diagnosis in a Danish series.

The investigation of 5547 prenatal diagnoses showed 31 unexpected structural chromosome rearrangements. These included 3 Robertsonian translocations, 14 reciprocal translocations and 14 inversions. All were balanced, including 5 de novo rearrangements. In 3 of these cases an induced abortion was performed and in 2 cases children without detectable malformations were delivered.