Clinical validation

Prenatal Diagnosis, one of the most prestigious journals in prenatal diagnosis field, has recently published - dedicating the cover - a prospective study conducted by the GENOMA Group Research Team on the clinical utility of the PrenatalSafe® Karyo test.

Aim of the study
The aim of the study was to evaluate the PrenatalSAFE® Karyo test clinical utility (which extends the analysis to all chromosomes by detecting both aneuploidies and structural chromosomal abnormalities) compared to traditional NIPTs (which restrict the analysis to only 5 chromosomes: 21, 18, 13, X and Y), and, at the same time, to evaluate the influence of the increase in sensitivity on specificity. The study was conducted on clinical samples.

Method and materials
In the study, where recruited 12.114 pregnant women (both high and low risk pregnancies) who underwent the non-invasive screening test of fetal aneuploidies common in pregnancy (Trisomy 21, Trisomy 18, Trisomy 13 and X and Y sex chromosomes aneuploidies), by analysing circulating free fetal DNA (cfDNA). Blood samples collected from the pregnant women were analysed, as well as with a traditional NIPT for the research of aneuploidy on the 5 chromosomes, even with a genome-wide technology to detect aneuploidies and structural chromosomal abnormalities extending the analysis to the entire karyotype, i.e. with the technology used by the PrenatalSAFE® Karyo test.

Obtained results
Il test PrenatalSAFE® Karyo test allowed to identify 18/169 (10.7%) pregnancies with fetal chromosomal abnormalities of clinical significance that a traditional NIPT could not detect, 12 (7.4%) of which could have been completed and result in the birth of children with chromosomopathies. Data from the study demonstrate the clinical utility of PrenatalSAFE® Karyo test that, compared to traditional NIPTs, increased the sensitivity from 92.64% to 100% (p<0.001). Furthermore, the results show that despite the increased sensitivity obtained with the screening level of the fetal karyotype, the test specificity did not decrease significantly, only diverging 0.1% from the specificity of a traditional NIPT (99.77% vs 99.87%, p=0.064).

* Clinically relevant chromosomal abnormalities, not detected by conventional cfDNA screening, potentially resulting in the birth of babies with chromosomal anomalies, have been considered as false negative. § A P-value of less than 0.05 was considered to indicate statistical significance.

Highlighting the importance of non-invasive screening of the entire fetal karyotype, the study confirmed the usefulness of the new method not only to detect aneuploidies on all fetus’ chromosomes, but especially for the research of structural abnormalities (deletions and duplications of chromosome portion), possible only with the latest high-resolution technology, such as the one used in the PrenatalSAFE® Karyo test.