Prevalence of recurrent pathogenic microdeletions and microduplications in over 9500 pregnancies

The constant a priori risk for common pathogenic cryptic imbalances detected by this technology is estimated to be ~0.3%. A prevalence higher than that previously estimated was found for the 22q11.2 microdeletion. Their frequencies were independent of maternal age. These data have implications for cell-free DNA screening tests design and justify prenatal screening for 22q11 deletion, as early recognition of DGS improves its prognosis.