Elly DeLaney Seminar Presentation 2

1. Elly DeLaneySeminar Presentation 2 Patterson C., Monk E., McAllion S. 2001. How common is hearing impairment in osteogenesis imperfecta? J. of Laryngology & Otology 115: 280-282.

2. Background • Osteogenesis imperfecta (OI) is a genetic disorder characterized by bones that break easily for little or no cause. There are 4 main types of OI.

3. Types of Osteogenesis Imperfecta Type I Most common and mildest type of OI. Bones predisposed to fracture. Most fractures occur before puberty. Normal or near-normal stature. Loose joints and low muscle tone. Sclera (whites of the eyes) usually have a blue, purple, or gray tint. Triangular face. Tendency toward spinal curvature. Bone deformity absent or minimal. Brittle teeth possible. Hearing loss possible, often beginning in early 20s or 30s. Collagen structure is normal, but the amount is less than normal.

4. Type II • Most severe form. • Frequently lethal at or shortly after birth, often due to respiratory problems. In recent years, some people with type 2 have lived into young adulthood. • Numerous fractures and severe bone deformity. • Small stature with underdeveloped lungs. • Collagen is improperly formed • Autosomal dominant type (the other 3 are autosomal recessive).

5. Type III • Bones fracture easily. Fractures often present at birth, and x-rays may reveal healed fractures that occurred before birth. • Short stature. • Sclera have a blue, purple, or gray tint. • Loose joints and poor muscle development in arms and legs. • Barrel-shaped rib cage. • Triangular face. • Spinal curvature. • Respiratory problems possible. • Bone deformity, often severe. • Brittle teeth possible. • Hearing loss possible. • Collagen is improperly formed.

6. Type IV • Between Type I and Type III in severity. • Bones fracture easily, most before puberty. • Shorter than average stature. • Sclera are white or near-white (i.e., normal in color). • Mild to moderate bone deformity. • Tendency toward spinal curvature. • Barrel-shaped rib cage. • Triangular face. • Brittle teeth possible. • Hearing loss possible. • Collagen is improperly formed.

7. Hearing Loss in OI • In 1912 Adrair-Dighton first noticed that hearing loss is an associated feature of OI. • Studies have confirmed that conductive defects, particularly due to abnormalities in the stapes are common causes of hearing loss in patients with OI.

8. The Ear • Number 10 is the stapes.

9. The Stapes • The smallest bone in the body is the stapes (stirrup). The stapes is the connection between the middle and inner ears.

10. Purpose • How common is hearing loss in OI? • At what age can OI patients expect to develop hearing loss?

11. Method • 1394 patients with OI were available for study. • Questionnaires were administered to patients in each case • In 833 cases (58.2%), patients were interviewed and examined personally

12. Results • 317 patients in the whole group were aware of hearing impairment at the time of the most recent evaluation • Results indicated that most OI patients who experienced hearing loss first develop symptoms in the first four decades of their lives.

13. Proportion of OI Patients who had Symptoms of Hearing Impairment at Each Decade

14. Age of Onset VS Number of patients

15. Proportion of OI of Each Type Who Has Symptoms by Age 30

16. DISCUSSION • Stimulation to explore this field. • Hearing impairment first noted most commonly in 2nd – 4th decades of life. • Recognition that study could not include evaluations of each patient for the exact type of hearing loss, but large number of patients did provide insight.

17. QUESTIONS?

18. References • Osteogenesis Imperfecta Foundation. Retrieved Jan. 31, 2002 at www.oif.org • Patterson C., Monk E., McAllion S. 2001. How common is hearing impairment in osteogenesis imperfecta? J. of Laryngology & Otology 115: 280-282 • www.sickkids.on.ca/auitorysciencelab/picturesl.asp