Osteogenesis Imperfecta Flashcards
What is the genetic cause of a patient how has experienced multiple bone fractures with minimal trauma and has blue sclera?
Osteogenesis Imperfecta (OI)
Mutations in COL1A1 or COL1A2 genes, leading to defective type I collagen synthesis.
The most common inheritance pattern is autosomal dominant.
There are many subtypes:
- Type I is mild
- Type III and IV are moderate forms
- Type II is severe and often leads to fetal demise
What are the hallmark clinical features of Osteogenesis Imperfecta?
- multiple fractures with minimal trauma
- bone deformities (short stature and scoliosis)
- blue sclerae due to translucent scleral collagen
- dental imperfections (dentinogenesis imperfecta)
- hearing loss due to abnormal ossicles
- easy bruising
What is the pathophysiology of blue sclerae in Osteogenesis Imperfecta?
The sclerae are thin and poorly formed due to impaired type I collagen and allow the revealing of the deeper choroidal veins, giving a bluish hue.
in other words …
Blue sclerae result from the translucent scleral collagen revealing underlying choroidal veins due to defective type I collagen synthesis.
How can Osteogenesis Imperfecta be distinguished from child abuse?
OI may mimic child abuse due to recurrent fractures, but hallmark features such as blue sclerae, dentinogenesis imperfecta, and hearing loss can help differentiate it.
Genetic testing for COL1A1/COL1A2 mutations confirms the diagnosis.
What is the mnemonic ‘BITE’ for Osteogenesis Imperfecta?
‘BITE’ stands for:
- Bones (multiple fractures)
- I (eye, blue sclerae)
- Teeth (dental imperfections)
- Ear (hearing loss)
What is the recommended treatment for Osteogenesis Imperfecta?
Treatment includes bisphosphonates to reduce fracture risk, physical therapy, and surgical intervention for severe deformities. Supportive measures like bracing and assistive devices may also be needed.
What dental abnormalities are associated with Osteogenesis Imperfecta?
Dentinogenesis imperfecta, characterized by opalescent teeth that wear easily due to a lack of dentin, is a common dental abnormality in OI.
What audiological findings are seen in Osteogenesis Imperfecta?
Hearing loss occurs due to abnormal ossicles, which can impair sound conduction in the middle ear.
What type of fractures are typical in Osteogenesis Imperfecta?
Patients experience multiple fractures and bone deformities after minimal trauma, including fractures during birth in severe cases.
What is diagnostic for Osteogenesis Imperfecta?
Clinical with genetic testing for COL1A1 or COL1A2 genes.
What role do bisphosphonates play in managing Osteogenesis Imperfecta?
Bisphosphonates inhibit osteoclast activity, reducing bone resorption and fracture risk in patients with OI.
