Hypermobility--not a circus act.

Joint hypermobility results from genetic variations in connective tissue matrix proteins resulting in stretchier tissues. For many it is an asset that confers greater facility for physical prowess. Others, less fortunate, fall prey to the associated effects of tissue fragility. The most frequently encountered constellation of traumatic and overuse injuries is termed the (benign joint) hypermobility syndrome (BJHS). This condition, poorly understood, frequently overlooked, misdiagnosed and inappropriately treated, is the cause of much needless suffering and anguish. Accumulating evidence suggests that BJHS represents a forme fruste of an heritable disorder of connective alongside Marfan syndrome, Ehlers-Danlos syndrome and osteogenesis imperfecta, with which it shares many overlapping features, but from which it can be phenotypically distinguished on the basis of clinical features and prognosis. The responsible gene defects have yet to be elucidated.