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Updated: Jul 23, 2026
10:03
Tissue Preparation and Immunostaining of Mouse Craniofacial Tissues and Undecalcified Bone
Published on: May 10, 2019
Nasal bone hypoplasia in trisomy 21 at 15-22 weeks' gestation
S Cicero1, J D Sonek, D S McKenna
1Harris Birthright Research Centre for Fetal Medicine, King's College Hospital, London, UK.
Summary
Ultrasound examination of the fetal nasal bone between 15-22 weeks
Area of Science:
- Medical Imaging
- Prenatal Diagnostics
- Genetics
Background:
- Prenatal diagnosis of trisomy 21 (Down syndrome) is crucial for genetic counseling and management.
- Ultrasound markers play a role in prenatal screening for chromosomal abnormalities.
- The fetal nasal bone is a potential marker for trisomy 21, but its utility requires further investigation.
Purpose of the Study:
- To evaluate the diagnostic value of fetal nasal bone assessment via ultrasound in identifying trisomy 21.
- To determine the incidence of nasal bone hypoplasia in fetuses with trisomy 21 and chromosomally normal fetuses.
- To calculate the likelihood ratios for trisomy 21 based on nasal bone presence or hypoplasia.
Main Methods:
- Observational ultrasound study involving 1046 singleton pregnancies.
- Fetal profile examination for nasal bone presence or hypoplasia was performed before amniocentesis.
- Nasal bone hypoplasia was defined as absent or shorter than 2.5 mm.
Main Results:
- Nasal bone hypoplasia was detected in 61.8% of trisomy 21 fetuses versus 1.2% of chromosomally normal fetuses.
- The likelihood ratio for trisomy 21 with hypoplastic nasal bone was 50.5, and for present nasal bone was 0.38.
- Nasal hypoplasia was observed in 8.8% of Afro-Caribbean and 0.5% of Caucasian chromosomally normal fetuses.
Conclusions:
- Fetal nasal bone hypoplasia identified via ultrasound between 15-22 weeks' gestation is a significant indicator of trisomy 21.
- This ultrasound finding demonstrates high sensitivity and specificity as a marker for trisomy 21.
- The assessment of fetal nasal bone status contributes to improved prenatal screening for trisomy 21.
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