Detection of 22q11.2 deletion syndrome by single-nucleotide polymorphism based non-invasive prenatal test

Abstract

Non-invasive prenatal test (NIPT) has become a popular screening test worldwide for screening common trisomies. In addition, the test can also sex chromosomal aneuploidies (SCAs) with similar sensitivity. In recent years, the scope of NIPT has extended to screen pregnancies for clinically significant microdeletions (MDs), rare autosomal aneuploidies, and subchromosomal abnormalities. The clinical utility of NIPT screening beyond trisomies 21,18,13 and SCAs are still being evaluated because of low positive predictive value which in turn leads to an increase in invasive procedures. Here, we present a case where SNP - NIPT correctly identified a microdeletion syndrome, i.e., 22q11.2DS in a pregnant woman with normal ultrasound findings. This NIPT finding was further confirmed in the chromosomal microarray study and FISH.