Osteogenesis Imperfecta: Definition, Types, Clinical Features, Radiographical Features, Histological Features | Dentistry. As the name denot...
Osteogenesis Imperfecta: Definition, Types, Clinical Features, Radiographical Features, Histological Features | Dentistry.
As the name denotes, there is the defective formation of the bone which means there is a failure in the transformation of procollagen into mature collagen. These are present in the Type I Collagen where there is defective matrix formation and lack of mineralization because of that the bone is not formed properly which results in increased bone fragility.
It is the autosomal dominant inherited disorder. It mainly affects the bone, eyes, teeth, and ear. It has established when there is a defect in Collagen, Type 1, Alpha-1 Chain (COL1A1 Gene) or Collagen, Type 1, Alpha-2 Chain (COL1A2 Gene). It is also called Brittle Bone Disease.
For the child who is suffering from osteogenesis imperfecta, they encounter multiple bone fractures usually. The bone grows to the normal length, but the bone is very thin and lacks a normal formation of the bone. As I told you earlier, bone fragility is the characteristic feature of osteogenesis imperfecta which results in multiple fractures.
Types of Osteogenesis Imperfecta
Type I
The features are mild deformity problems of bones, presence of blue sclera, defective formation of dentin, deafness, hypermobility of the bone joints, and disorders related to heart valves. It includes two subtypes. In subtype A dentinogenesis imperfecta is present while in subtype B dentinogenesis imperfecta is absent.
Type II
In this type of osteogenesis imperfecta, the child will die before death or perinatal death.
Type III
There is the presence of severe bone deformity and blue-colored sclera. Dentinogenesis imperfecta is associated with this type.
Type IV
Presence of few fractures of the bone with the normal sclera and no risk to the life. It has also two subtypes. In Subtype A, dentinogenesis imperfecta is absent and in Subtype B, dentinogenesis imperfecta is present
Clinical Features of Osteogenesis Imperfecta
Crowns are bulbous in nature which is either blue or brown in color. There is a presence of multiple fractures of the bones due to the increased fragility of the bones. There is a possibility for hearing loss which is due to obliterated or closure of cranial foramen which results in diminish and can cause compression of nerves passes through it. Hypermobility of the joint is present. Class III Malocclusion is seen which is due to maxillary hypoplasia. Crossbite is also seen. The excessive bruising tendency of the patient due to osteomyelitis usually after extraction can see this. Also, dentinogenesis imperfecta is associated with 25% of cases of osteogenesis imperfecta.
Radiological Features of Osteogenesis Imperfecta
Presence of wormian bones in the skull. These are the multiple small sutures in the skull arranged in the mosaic bone pattern of the bone. Deformity of the long bones, as well as multiple fractures, are also seen in the radiological findings.
Histological Features of Osteogenesis Imperfecta
There is a presence of immature woven bone formed due to failure in the process of mature collagen formation. Thinning of the cortex is also seen.
Treatment
Some studies suggest that bisphosphates are given to the child from birth and it is stopped from 18-21 years of age where the normal growth is arrested. Bisphosphates help in the growth of the bone by thickening the cortex. Prognosis may vary depending upon the severity of the disease. But, To date there are no cases is reported by the use of Bisphosphates. To date, there is no known treatment for Osteogenesis Imperfecta.
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