Cell-free DNA analysis of maternal blood in prenatal screening for chromosomal microdeletions and microduplications: a systematic review.

BACKGROUND AND AIM OF THE STUDY: Scientific Societies do not recommend the use of cell-free DNA (cfDNA) testing as a first-tier screening for microdeletion and microduplication syndromes (MMs). The aim of this study was to review the current available literature on the performance of cell-free DNA as a screening for MMs. METHODS: Medline, Embase and the Cochrane Library were searched electronically from 2000 to January 2020 and articles reporting the diagnostic performance of cfDNA screening for MMs in large (>5000 cases) series were included. Between-study heterogeneity and random effect model for screen positive rate (SPR), false positive rate (FPR) and positive predictive value (PPV) were calculated. RESULTS: We identified 42 papers, seven included, for a total of 474,189 pregnancies and 210 cases of MMs. Diagnostic verification of positive cases was available overall in 486 (71.68 %) of 678 cases. The weighted pooled SPR, FPR and PPV were 0.19% (95% CI = 0.09-0.33), 0.07 (95% CI = 0.02-0.15) and 44.1 (95% CI = 31.49-63.07). In conclusion, the pooled PPV of cfDNA testing in screening for MMs was about 40%, ranging from 29% to 91%, for an overall FPR <0.1%. CONCLUSIONS: No confirmatory analysis was available in cases that did not undergo invasive testing, which were the vast majority of cases with a negative test, and therefore, the DR and the negative predictive value cannot be determined.

Survey of second-trimester maternal serum screening in Japan.

AIM: Second-trimester maternal serum screening (MSS) is the predominant form of prenatal screening in Japan. We hypothesize that patient education and physician knowledge of Down syndrome (DS) screening are insufficient to provide adequate information regarding prenatal screening in Japan. MATERIAL AND METHODS: In-person or telephone interviews with medical personnel were conducted at 25 medical facilities utilizing Afp(4) (Esoterix Genetic Laboratories, LLC, a wholly-owned subsidiary of Laboratory Corporation of America Holdings) second trimester screening. We explored how medical facilities provided information about the MSS process to pregnant women. RESULTS: Before prenatal testing, 60% of medical facilities spent an average of less than 5 min per patient explaining the MSS process. The option of amniocentesis for chromosomal aneuploidy was explained at nearly all facilities, but only 60% explained the risk of amniocentesis. Ultrasound examination for open neural tube defects was explained only at half the facilities. Only five of 25 (20%) medical practitioners explained the possibility of having congenital disorders fetus. CONCLUSION: This study revealed that most obstetricians in Japan do not provide their patients with sufficient information about MSS.