title: Absence of nasal bone and detection of trisomy 21.
authors.forename: Pierangela
authors.initials: P
authors.lastname: De Biasio
authors.forename: Pier Luigi
authors.initials: PL
authors.lastname: Venturini
mesh_terms: D004314:Down Syndrome / Q000175:diagnosis*; D005260:Female; D006801:Humans; D009295:Nasal Bone / Q000002:abnormalities / Q000000981:diagnostic imaging*; D011247:Pregnancy; D015203:Reproducibility of Results; D016216:Ultrasonography, Prenatal