• INCLUSION CRITERIA:

Children will be recruited from the United States. This recruitment will be accomplished by our contacts with the Osteogenesis Imperfecta Foundation, parent-to-parent communication, and outside referrals from other health care providers.

There are no exclusionary criteria related to race or gender for this protocol.

Children enrolled in this study will be limited to those with Sillence Types III and IV OI, as determined by clinical and genetic criteria.

Patients age birth to 10 years at enrollment will be considered for this protocol.

Children who have not had skin biopsy done for collagen analysis at another facility are preferred for participation in this study. However, previous skin biopsy at another facility will not preclude participation in this protocol.

EXCLUSION CRITERIA:

Children who can be expected to attain at least some degree of ambulatory skill or have high potential for achieving independent locomotion with assistive technology.

Children who are clinically too severe to benefit from this program are defined by the following criteria:

1. The ratio of head circumference age (the age for which the child's head or body size falls at the 50th percentile) to body length age (the age for which the child's length falls at the 50th percentile) is 7:1 or greater;
2. Children who are 24 months of age, and who are unable to sit unsupported for 60 seconds and are unable to demonstrate the ability to prop themselves on upper extremities in the prone position;
3. Children who have other significant medical problems, especially severe cardiopulmonary problems, which have an impact on their physical development.

Compliance with the visit schedule, maintenance of the physical therapy program, and completion of the measurement tools are central to our analysis of the outcomes of this study. Failure to comply with these conditions will constitute exclusion criteria.