Author Contributions: Dr Li had full access
to all of the data in the study and takes responsibility for the integrity
of the data and the accuracy of the data analysis.
Study concept and design: Li, Di Naro, Vitucci,
Acquisition of data: Li, Di Naro, Vitucci,
Analysis and interpretation of data: Li, Zimmermann,
Drafting of the manuscript: Li, Hahn.
Critical revision of the manuscript for important
intellectual content: Li, Di Naro, Vitucci, Zimmermann, Holzgreve,
Statistical analysis: Li.
Obtained funding: Holzgreve, Hahn.
Administrative, technical, or material support:
Di Naro, Vitucci, Zimmermann, Hahn.
Study supervision: Hahn.
Financial Disclosures: Drs Li, Zimmerman, Holzgreve,
and Hahn have filed for a patent covering the use of size-fractionated DNA
for noninvasive prenatal diagnosis. This patent is owned by the University
Hospital, Basel, Switzerland. Drs Di Naro and Vitucci reported no financial
Funding/Support: This study was supported by
the European Union FP6 Network of Excellence “SAFE,” as well as
funds from the University Women’s Hospital/Department of Research, University
Hospital, Basel, Switzerland.
Role of the Sponsor: The European Union FP6
Network of Excellence “SAFE” and the University Women’s
Hospital/Department of Research did not participate in the design and conduct
of the study, in the collection, analysis, and interpretation of the data,
or in the preparation, review, or approval of the manuscript.
Acknowledgment: We thank Susanne Mergenthaler,
PhD, and Corinne Rusterholz, PhD, for valuable discussions and critical evaluation
of the final manuscript.