Molecular analysis by fluorescence in situ hybridization of a prenatally detected de novo complex chromosomal rearrangement t(2q;3p;4q;13q).

We report one case of de novo complex chromosomal rearrangement (CCR) t(2q;3p;4q;13q) with at least five chromosomal breakpoints. This CCR was detected prenatally at 22 weeks of gestation, when mild echographic indications were disclosed during a routine examination in a female with no family history of congenital abnormalities. This observation clearly illustrates what the fluorescence in situ hybridization (FISH) technique can offer to the analysis of such rearrangements, together with standard cytogenetic techniques. No chromosomal imbalance was cytologically proved. Nevertheless, the status of the infant at birth and the disorders that he exhibited during the following months demonstrate once again that even in the absence of alarming ultrasonographic verifications and even if standard and molecular cytogenetics do not allow us to confirm evident chromosomal imbalances, genetic counselling in the case of prenatally detected de novo CCR must remain cautious.