Osteogenesis imperfecta
Osteogenesis imperfecta also known as Brittle Bone Disease or Lobstein syndromeIt is a group of diseases where there is an increased fragility of bone with frequent fractures.
They are all associated with type I collagen mutations.It is a genetic disorder with autosomal dominant inheritance
Mainly there are four subtypes of Osteogenesis imperfecta
Type I mild disease(Collagen is of normal quality but is produced in insufficient quantities)
1. Blue sclerae
2. Slight protrusion of the eyes
3. Mild prepubertal bone fragility
4. Little or no deformity or Slight spinal curvature
5. Loose joints
6. Mild short stature
7. Poor muscle tone
8. Hearing loss in about 50% of adults
9. Bruises easily
10. Dentinogenesis imperfecta may be absentin 1A and present in 1B
Type II perinatal lethal(Collagen is not of a sufficient quality or quantity)
1. Most cases die within the first year of life due to respiratory failure or intracerebral hemorrhage
2. blue sclerae
3. In utero fractures
4. Micromelia
5. Marked long bone deformity
6. Platyspondyly
7. Lethal in the perinatal period
8. Broad but poorly mineralized skull
Type III progressive deforming(Collagen quantity is sufficient but is not of a high enough quality)
1. Blue then white sclerae
2. Progressing deforming of the long bones and spine secondary to fractures and gravity
3. Relative macrocephaly and triangular faces
4. Extremely short stature and barrel-shaped rib cage
5. Respiratory problems
6. Poor muscle tone and Loose joints
IV moderately severe disease(Collagen quantity is sufficient but is not of a high enough quality)
1. White sclerae
2. Moderate fragility and mild to moderate bowing of long bones especially before puberty
3. Variable short stature
4. Dentinogenesis imperfecta absent in IVA and present in IVB