Screening of candidates will be based on telephone interviews with a parent, and referral records to include: AP and lateral radiographs of the lower extremities and spine, and family, developmental, fracture and medical history. An NIH clinical screening evaluation will be performed for those children who appear to have a history consistent with OI under protocol 04-CH-0077, Screening of and Diagnosis of Patients with Connective Tissue Disorder . Patients admitted for this screening visit who are less than four years of age as well as those older than 4 years of age but not meeting the criteria for inclusion in the growth hormone protocol, protocol 92-CH-0034, will be considered for enrollment in protocol 97-CH-0064 (Evaluation and Intervention for Ambulation, Growth and Basilar Invagination in OI), those older than four years who meet the criteria will be considered for co-enrollment in protocol 92-CH-0034.