Pitfalls in prenatal diagnosis: cytogenetic analysis in amniocytes fails to detect mosaic r(12)

Abstract

The chance of missing such a supernumerary ring mosaicism is very low (about 2% in our case). Given its very rare occurrence and the low chance of it being missed if the existing Dutch guidelines are followed, adapting the number of cells or colonies to be examined for all prenatal diagnoses does not appear to be justified.