OSTEOGENESIS IMPERFECTA

• Heterogeneous group of disorders involving abnormalities of type l collagen.
• The mutation causes abnormal pro - alfa l chains of type l procollagen. The aberrant protein is produced by amniocytes and chorionic villi in affected pregnancies and may be detected by gel electrophoresis.

ULTRASOUND

Link to Ultrasound Appearance Of The Lethal Form (Type II)

CLASSIFICATION

Type	Mode of inheritance / form	Age	Description	Antenatal Ultrasound
I	Dominant/ Regressive	2-6 yr	Mild fragility. No deformity. Mild-moderate short stature. Blue sclera. Hearing loss. 1A- Dentinogenesis imperfecta absent. 1B- Dentinogenesis imperfecta present.	Mild bowing of long bones. No fractures. No IUGR.
II	Dominant or Recessive / Lethal	Peri- Natal	Extreme fragility of connective tissue. Blue Sclera. Loose skin. Stillborn or perinatal death due to pulmonary hypoplasia.	Short broad bones. Fractured bones. Bone demineralization. Thick callous. Ribs - thin & beaded, +/- fractures; bell shaped chest. Skull - poor ossification.
III	Recessive or Dominant / Severe		Progressive deformities compatible with life. Blue sclera (becomes pale). Progressive limb and vertebral anomalies into adulthood.	Short bowed bones. Multiple fractures at birth (2/3). Skull - decreased ossification. Normal vertebrae, pelvis. Humerus normal. Chest normal.
IV	Dominant Regressive		Mildest form. Best prognosis. Normal sclera color.	Normal tubular bones. Mild femoral bowing. Osteoporosis.

REFERENCES

1. Merz E, Goldhofer W. Sonographic Diagnosis of Lethal Osteogenesis Imperfecta in the Second Trimester: Case Report and Review. J Clin Ultrasound 1986, 14:380-383.
2. Munoz C, Filly RA, Golbus MS. Osteogenesis Imperfecta Type II: Prenatal Sonographic Diagnosis. Radiology 1990, 174:181-185.