Osteogenesis imperfecta type II: prenatal sonographic diagnosis

Area of Science:

• Prenatal diagnosis
• Fetal medicine
• Skeletal dysplasias

Background:

• Osteogenesis imperfecta type II is a lethal congenital disorder.
• Accurate prenatal diagnosis is crucial for genetic counseling and management.
• Distinguishing OI type II from other fetal skeletal abnormalities can be challenging.

Purpose of the Study:

• To evaluate the diagnostic accuracy of specific sonographic criteria for fetal osteogenesis imperfecta type II.
• To determine if these criteria can differentiate OI type II from other osteochondrodysplasias.
• To establish the utility of a normal ultrasound in excluding OI type II in at-risk pregnancies.

Main Methods:

• Retrospective blind review of fetal sonograms from pregnancies at risk for osteogenesis imperfecta type II.
• Correlation of sonographic findings with pregnancy outcomes.
• Evaluation of proposed diagnostic criteria: multiple fractures, calvarial demineralization, and femoral length < 3 SDs.

Main Results:

• Six of eight cases of osteogenesis imperfecta type II were correctly diagnosed using the proposed criteria.
• Two undiagnosed cases had abnormalities but did not meet all three criteria.
• All 18 unaffected at-risk fetuses and 25 fetuses with other osteochondrodysplasias did not meet the diagnostic criteria.

Conclusions:

• Strict sonographic criteria can reliably diagnose fetal osteogenesis imperfecta type II.
• This diagnostic approach effectively distinguishes OI type II from other fetal skeletal abnormalities.
• A normal fetal ultrasound after 17 weeks gestation excludes lethal osteogenesis imperfecta type II in at-risk pregnancies.