Types of Ostegenesis Imperfecta
TYPE II – Extremely severe
OI Type II is the most severe form of osteogenesis imperfecta. With Type II, the collagen is not of a sufficient quality or quantity. Most patients with this case die within the first year of life due to respiratory failure or intracerebral hemorrhage. Severe respiratory problems result from the underdevelopment of the lungs. Genetic counseling is recommended for parents of a child with OI Type II before any future pregnancies. General features of OI Type II are the following:
- At birth, infants with OI Type II have very short limbs, small chests, and soft skulls. Their legs are often in a frog-leg position.
- Intrauterine fractures will be evident in the skull, long bones, or vertebrae.
- The sclerae are usually very dark blue or gray.
- The lungs are underdeveloped.
- Infants have low birth weights.
- Respiratory and swallowing problems are common.
- Macrocephaly may be present. Microcephaly is rarely present.
Type III – Severe
OI Type III is the most severe type among children who survive the neonatal period. The degree of bone fragility and the fracture rate vary widely. Patients with Type III OI have improperly formed collagen. There is enough collagen made however, it is defective. General features of OI Type III are the following:
- At birth, infants generally have mildly shortened and bowed limbs, small chests, and a soft calvarium.
- Respiratory and swallowing problems are common in newborns.
- There may be multiple long-bone fractures at birth, including many rib fractures
- The head is often large relative to body size. A triangular facial shape, due to overdevelopment of the head and underdevelopment of the face bones, is characteristic.
- The sclerae may be white or tinted blue, purple, or gray.
- Early loss of hearing possible
- Poor muscle tone in arms and legs