Changes of elastic fibers in musculoskeletal tissues of Marfan syndrome: a possible mechanism of joint laxity and skeletal overgrowth.

The aim of the study was to analyze by histochemical, ultrastructural, and morphometric methods the musculoskeletal tissues in three humans affected with Marfan syndrome. Histochemical and morphometric data demonstrated that the content of elastic fibers in the perichondrium, periosteum, and knee capsule of the individuals with Marfan syndrome was dramatically reduced in comparison with control tissues. Ultrastructurally the elastic fibers appeared fragmented and indented, because of the presence of discontinuous aggregates of elastin among randomly dispersed filaments. These abnormalities of the articular capsule argue that these fibers could be functionally incompetent to resist normal stress, predisposing to joint laxity. Moreover, alterations in both perichondrium and periosteum seems to support our previous hypotheses about the control of long-bone growth exerted by elastic fibers.