The most frequently detected chromosomal anomalies in amniotic fluid or chorionic villi samples are aneuploidies, which consist in the presence or absence of one or more copies of chromosomes 13, 18, 21, X and Y. The aneuploidies of these 5 chromosomes represent roughly 70% of all chromosomal anomalies detected.
Rapid prenatal diagnosis consists in a test which does not require a cell culture of samples of foetal origin. According to the technique selected, the analysis can exclusively address the 5 above-mentioned chromosomes (QF-PCR), or may also include the study of 9 frequent microdeletions/microduplications syndromes (BoBs) which cause different types of brain damage or psychomotor retardness in newborns.