Natera, Inc. announced the publication of the landmark SMART study in the American Journal of Obstetrics and Gynecology(AJOG). The SMART study enrolled more than 20,000 patients at 21 medical centers globally and is the largest prospective non-invasive prenatal testing (NIPT) study ever performed. All results included in the analysis were validated with genetic confirmation.

This publication focuses on the performance of SNP-based NIPT (Panorama) to screen for 22q11.2 deletion syndrome (22q11.2DS); a separate publication will report on test performance for the common aneuploidies. Key findings include: 22q11.2DS had a higher-than-expected prevalence of 1/1,524 pregnancies in this cohort. This is comparable to other conditions broadly recommended for routine screening, such as cystic fibrosis (~1 in 2,500).

Panorama was able to detect all cases of the most common (2.5-3Mb) 22q11.2DS, and 83% of all 22q11.2DS. Panorama's false positive rate was low, 0.05%, resulting in a positive predictive value (PPV) of 53% or 1 in 2. For context, historical serum screening tests have PPVs of ~3% or 1 in 29 for trisomy 21. None of the patients with a pregnancy affected by 22q11.2DS had an abnormal first trimester ultrasound, highlighting the unique potential of NIPT to add valuable information early in pregnancy.