OI is often inherited from an affected parent. The diagnosis of OI is made on the basis of family history and/or clinical presentation. Frequent fractures, short stature, a blue hue to the white part of the eye (blue sclera), teeth problems (dentinogenesis imperfecta) and hearing loss that progresses after puberty may be present.
X-rays are also used to diagnose OI. X-ray findings include fractures that are at different stages of healing; an unexpected skull bone pattern called Wormian bones; and bones in the spine called "codfish vertebrae."
Laboratory testing for OI may include either biochemical testing or DNA-based sequencing of COL1A1 and COL1A2. Biochemical testing involves studying collagens taken from a small skin biopsy. Changes in type I collagen are an indication of OI.
DNA sequencing of COL1A1 and COL1A2 is used to identify the type I collagen gene mutation responsible for the altered collagen protein. DNA testing requires a blood sample for DNA extraction. Both tests are relatively sensitive, detecting approximately 90 percent and 95 percent, respectively, of individuals with the clinical diagnosis of OI. Normal biochemical and molecular testing in a child with OI warrants additional testing of less common collagen genes (CRTAP and P3H (LEPRE1)) responsible for some of the rare recessive forms of OI.