Joint hypermobility is the dominant clinical manifestation. Generalized joint hypermobility that affects large (elbows, knees) and small (fingers, toes) joints is evident in the Hypermobility Type. Recurring joint subluxations and dislocations are common occurrences. Certain joints, such as the shoulder, patella and temporomandibular joint dislocate frequently. The skin involvement (smooth velvety skin with or without hyperextensibility) as well as bruising tendencies in the Hypermobility Type are present but quite variable in severity.
Chronic pain is a well-established and cardinal manifestation of Hypermobility EDS and it is common for pain to be out of proportion to physical and radiological findings. The origin of the pain is not clearly understood, but some of the likely causes include muscle spasm (tender points are sometimes present) and degenerative arthritis; neuropathic pain is also common.
To date, there is no distinctive biochemical collagen finding identified for the majority of Hypermobility cases. The Hypermobility Type of EDS is inherited in an autosomal dominant manner.