Non-skeletal Issues of Osteogenesis Imperfecta

Early definitions of osteogenesis imperfecta (OI) refer to a syndrome of fragile bones plus hearing loss. This suggests that the problems seen in people with OI include more than just brittle bones. In dominant OI, the mutation in type 1 collagen affects not only the skeleton but also the collagen-rich tissues in other organ systems. Like the skeletal manifestations, the non-skeletal clinical features vary in the degree of severity. In some instances, age is also a factor in severity. Research is needed to fully understand the prevalence and best approach to management of non-skeletal issues.

More detailed information and recommendations for many of the following topics is provided in the Supporting Documents for this section.

Dental Oral-Facial

OI affects the growth of both jaws and tooth development. In addition, about 50% of people with OI also have dentinogenesis imperfecta (DI). Regular dental care is recommended for all people with OI beginning within 6 months after the primary teeth erupt and continuing throughout life. Other common oral cavity problems related to OI include impacted teeth, anterior and posterior open and cross bites and skeletal Class III malocclusion.

Pulmonary

In people with severe forms of OI respiratory complications are a leading cause of death. Although respiratory problems are usually more severe in those with severe OI, the primary collagen defect affects lung tissue in all people with OI, including those with a mild phenotype. Altered lung tissue predisposes the person to respiratory infections.

Rates of asthma and pneumonia are higher in children and adults who have OI than in the unaffected population. Chest wall deformities, rib fractures, scoliosis, kyphoscoliosis, chest wall muscle weakness, limited mobility and the effects of gastrointestinal problems such as constipation and reflux all contribute to poor pulmonary function. Fatigue, breathlessness and wheezing are frequent symptoms. Manifestations can include asthma, recurrent pneumonia, exercise intolerance, and sleep apnea.

Hearing

Approximately 50% of adults with OI have a measurable hearing loss, which typically arises in the second or third decade of life. Bone quality and structural abnormalities of the ear bones -- including visible deformities in the ossicles and inner ear-- contribute to the loss. Environmental factors affecting hearing may cause a loss sooner than in the unaffected population. Most hearing loss in OI is mixed but conductive, and sensorineural types of loss are seen. Severity ranges from mild to profound. In addition, some people report tinnitus and vertigo. Treatments include hearing aids and/or surgery such as stapedectomy or cochlear implant. Physicians should be alert to dangers of ototoxins in this population.

Cardiovascular

The prevalence of cardiovascular problems among patients with OI is unknown. The most frequently reported cardiovascular issues are hypertension, and mitral valve prolapse. Heart valve problems are believed to develop over time. They are more of a concern for adults who have OI, but are infrequently seen in children. Cardiac surgery, including valve replacement, has been successful.

Neurological

Intelligence is typically normal in OI. People with all subtypes of OI may develop basilar impression (BI) over time, and those with severe OI (Type III) have a greater risk. Enlarged head circumference is seen in infants and children who have OI and may or may not be caused by hydrocephalus. Evaluation is required; shunting is possible

Vision

People with OI seem to experience the common refractive errors such as myopia, hyperopia or astigmatism at about the same rate as people in the unaffected population. More serious conditions like glaucoma and retinal detachment are seen in adults, but the incidence is unknown. Blue sclerae, a frequently described finding, may be associated with corneal thinning. Scleral thickness is normal in OI Type I but may be thin in other types of OI.

Connective Tissue: Blood Vessels, Skin, Tendons and Ligaments

  • Thin blood vessels and thin skin may cause people to bruise easily.
  • Skin may be stiffer and less elastic, increasing the risk for scarring.
  • Reduced muscle strength may be significant in those with moderate and severe forms of OI.
  • Joint laxity is common and contributes to frequent sprains and dislocations particularly of the ankles, hips, shoulders, thumbs and elbows.
  • Flat feet are common, particularly in Type I (the mildest type).
  • Hernias may be present at birth and occur more frequently in children with OI than in the general population.

Endocrine

  • People with more severe forms of OI are often short however growth hormones and other hormones are typically normal.
  • Excessive diaphoresis has been reported in individuals of all types of OI.
  • Young women with OI may start menstruating later than other women.

Gastrointestinal

  • Constipation is common in children and adults with OI.
  • Spine, hip and pelvic deformities contribute to constipation in severely affected children.
  • Treatments include diet, hydration, physical activity and medication.
  • Celiac disease, gluten sensitivity, and colitis are reported in children, teens and adults with all types of OI, but it is not clear if these are more common than in the general population.

Pain

People who have OI experience acute pain from an injury; surgical pain; and varying degrees of chronic pain. Back pain may be due to compression fractures of the spine or spine curves such as scoliosis or kyphosis. Some people may have pain without clear evidence of a fracture. Adequate pain management is essential to maintaining mobility and improving quality of life. People with OI feel the same level of pain as others but may complain less since they experience pain more often than others.

 

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