Osteogenesis imperfecta. The set point proposal (a possible causative mechanism).

The minimum effective strain (MES) constitutes a threshold that separates biomechanically acceptable from unacceptable strains on growing bone and fibrous tissues. Strains above that threshold affect modeling and remodeling activities in ways that change the size and configuration of growing bones, tendons, ligaments, and fascia to fit their new mechanical usage and return their strains to the threshold level. Were that threshold set too high from birth, the effects of normal function on remodeling and modeling should lead to thin fibrous tissue structures, to slender, osteopenic diaphyses and spongiosa, and to increased fragility. Those and other predictable set point effects fit so precisely many of the known hard and soft tissue abnormalities of osteogenesis imperfecta patients, that an elevated MES set point may be a heretofore unrecognized basic pathogenetic factor in that disease.