Marfan syndrome and its disorder in periodontal tissues

Elastic system fibers are composed of two distinct elements, elastin, which is an amorphous component crosslinked in the core, and microfibril, localized in the periphery of elastin. As microfibrillar proteins, fibrillins, microfibril-associated glycoproteins (MAGPs), latent TGF-beta-binding proteins (LTBPs), microfibril-associated proteins (MFAPs), and fibulins are known. Fibrillin-1 is a major microfibrillar protein and characterized by calcium binding EGF-like (cbEGF) domain. Association between fibrillin-1 and TGF-beta is a recent topic of this field and this interaction is known to inactivate and target TGF-beta action. FBN1 encoding fibrillin-1 is a responsible gene for Marfan syndrome type 1 (MIM #154700), characterized by increased height and long limbs, ectopia lentis, and cardiovascular disorders, such as mitral valve prolapse and aortic dilation and regurgitation. Animal models suggest that the abnormal TGF-beta signaling is underlying as the pathogenesis of these conditions. Besides skeletal, ocular and cardiovascular conditions, severe periodontitis is frequently seen in affected patients. To clarify the unknown function of elastic system fibers in the periodontal ligament (PDL), PDL-cells were isolated from a Marfan syndrome type 1 patient who was with the severe periodontitis and had a mutation in one of the cbEGF domain of fibrillin-1. These results suggested that wild-type fibrillin-1 was required for the normal cell alignment and tissue architecture of PDLs. Evidences are now accumulated to suggest that fibrillin-1 is one of the molecule involved in the interaction between cell and extracellular matrix.