Rapid methods for targeted prenatal diagnosis of common chromosome aneuploidies.

Improvements in non-invasive screening methods for trisomy 21 (Down syndrome) and other aneuploidies during the first and second trimester of pregnancy have radically changed the indications for prenatal diagnosis over the last decade. Consequently, there was a need for rapid tests for the detection of common chromosome aneuploidies resulting in the development of molecular methods for the rapid, targeted detection of (an)euploidies of the chromosomes 13, 18, 21 and the sex chromosomes. The analysis of large series of prenatal samples has shown that such tests can detect the great majority of chromosome abnormalities in prenatal diagnosis. This resulted in lively discussions on whether conventional karyotyping should remain the standard method for the majority of prenatal cases or can be replaced by rapid tests only. This review gives an overview of different aspects of the three most common tests for rapid, targeted prenatal detection of (an)euploidies, i.e. interphase fluorescence in-situ hybridisation (iFISH), quantitative fluorescent polymerase chain reaction (QF-PCR) and multiplex ligation-dependent probe amplification (MLPA).