Concordance Study for Large Fetal Copy-Number Variants from Global NIPT Consortium

A retrospective cohort study of 276 cases evaluates concordance between genome-wide cell-free DNA screening and diagnostic test results for large fetal copy-number variants. The dataset includes 209 cases with diagnostic results, with a mean CNV size of 33.4 Mb and a mean gestational age of 13 weeks at blood draw. It was contributed by eight sites across seven countries, with 83% of cases from European locations.

Use Cases

• Calculate concordance rates between cfDNA screening and diagnostic test results for the 209 cases with available diagnostic data.
• Analyze the distribution of CNV size (mean 33.4 Mb, median 23.1 Mb) across deletion and duplication cases.
• Investigate the relationship between fetal fraction (mean 8.8% among concordant cases) and screening outcome.
• Assess the prevalence of plausible maternal biological explanations among the 157 discordant cases.
• Examine pregnancy outcome information available for 116 cases in relation to CNV type and size.

Strengths

• Contains 276 clinical cases with a single isolated cfDNA-identified CNV ≥7 Mb.
• Provides diagnostic test results for 209 cases (75.7% of the cohort) enabling direct concordance analysis.
• Includes key clinical metrics such as mean CNV size (33.4 Mb) and mean gestational age (13 weeks).
• Multi-site study with contributions from eight consortium sites across seven countries.

Limitations

• Limited sample size of 276 cases, which may restrict statistical power for subgroup analyses.
• Pregnancy outcome information is available for only 116 cases (42.0%), limiting longitudinal analysis.
• Parental testing results are available for only 38 cases (13.8%), reducing insights into heritability.

Provenance

Source

Global Expanded NIPT Consortium members, submitted via figshare by author Erica Soster.

Collection Method

Retrospective cohort study evaluating submitted clinical cases.

Time Range

Not explicitly stated in the provided description.

Freshness

Last updated March 2026.

Geography

Eight sites in seven countries, with 83% of cases submitted from European sites.