What is the hallmark diagnostic feature of the hypermobile type of Ehlers Danlos Syndrome?

The hallmark diagnostic feature of hypermobile Ehlers-Danlos Syndrome (hEDS) is joint hypermobility, which is characterized by an increased range of motion in joints beyond what is considered normal. This feature is a key criterion for diagnosing hEDS, as it can lead to various symptoms, including pain and increased susceptibility to joint dislocations and injuries.

Joint hypermobility in hEDS is often assessed through the Beighton score, which evaluates a combination of movements in various joints. Unlike other types of Ehlers-Danlos Syndrome, such as the classical type, hEDS lacks the marked skin hyperextensibility, fragility, or additional systemic features; thus, joint hypermobility stands out as the primary diagnostic indicator for this specific type.

Other features like skin hyperextensibility, heart murmurs, and bone fragility may be relevant to different types of Ehlers-Danlos Syndrome but are not central to the diagnosis of hEDS. For instance, skin hyperextensibility is more characteristic of the classical type, and heart murmurs may indicate vascular complications associated with another type, such as the vascular type of EDS. Bone fragility is also more associated with osteogenesis imperfecta rather than h