Hypermobile Connective Tissue Disorders & Laxity
What are Hypermobile disorders of connective tissue (HDCT) & EDS?
HDCT are a heterogenous collection of disorders of the connective tissue. Mutations affect collagen and the way it behaves resulting in tissue hyper-distensibility and joint laxity.
Specifically, mutations change the way collagen folds and organizes itself. Collagen has to form properly from DNA translation into RNA and transcription into protein structucture that must fold correctly to function properly. Mutations change the structure, folding, and function of collagen through changes in the collagen structures itself or the proteins that influence the cleavage, folding and, thus, behavior of collagen. The affected genes and the expression of these genes affect the degree of clinical signs and symptoms.
HDCT include Hypermobile Spectrum Disorders, Marfan's syndrome, osteogenesis imperfectca, and EDS.
EDS are a heterogenous group of inherited connective tissue disorders characterized by joint hypermobility, skin hyperextensibility, and tissue fragility. EDS are currently classified into thirteen subtypes with strict set of diagnostic criteria. Many of the the EDS subtypes have associated specific gene mutation except hypermobile EDS (hEDS). The hypermobility type is most common in EDS, followed by the classical type. Together, they account for approximately 90% of all cases
General categorization according to Voermans, N.C., Bonnemann, C.G., Hamel, B.C.J., et al., 2009. Joint hypermobility as a distinctive feature in the differential diagnosis of myopathies. J. Neurol. 256, 13–27.
I. Conditions with diffuse distal and proximal hypermobility: Marfans, Ehlers–Danlos classical type, tenascin-X and hypermobility type, central core disease
IA. Diffuse distal and less so proximal mobility – multiminicore disease
II. Distal hypermobility only – Ehlers–Danlos vascular and kyphoscoliotic types
III. Distal hypermobility and proximal contractures – Ulrich congenital myopathy, Bethlem myopathy, congenital muscular dystrophy with joint hypermobility (CMDH)
IV. Mixed pattern – limb girdle muscular dystrophy
What is hypermobility Spectrum Disorders?
Hypermobility spectrum disorders (HSD) are a group of conditions related to connective tissue laxity. HSD encompasses the syndrome of connective tissue disorders that don't meet the strict diagnostic criteria of hEDS. There is Hypermobility as measured by the Beighton score. Like hEDS, work up for other autoimmune and medical conditions is negative. Unlike hEDS, other specific clinical conditions are not present. HSD, just like hEDS, is multi-systemic. Those with HSD have variable laxity in different body regions have heterogeneous systemic involvement.
In general, the classification falls into the following:
Generalized (joint) HSD (G-HSD): GJH objectively assessed (e.g., by the Beighton score) plus one or more secondary musculoskeletal manifestations identified below. The pattern and severity of the musculoskeletal involvement should be carefully assessed in order to explore the possibility full-blown hEDS.
Peripheral (joint) HSD (P-HSD): JH limited to hands and feet plus one or more secondary musculoskeletal manifestations.
Localized (joint) HSD (L-HSD): JH at single joints or group of joints plus one or more secondary musculoskeletal manifestations regionally related to the hypermobile joint(s).
Historical (joint) HSD (H-HSD): self-reported (historical) GJH with negative Beighton score plus one or more secondary musculoskeletal manifestations. Physical examination aimed at excluding the alternative diagnoses of G-HSD, P-HSD, and L-HSD as well as other rheumatologic conditions is mandatory.
What are the consequences of laxity?
These disorders are multi-systemic and characterized by involvement of vessels, skin, joints, bone, organs, muscles, and nervous system. Hypermobility can be symptomless apart from the unusual mobility, but often there are other symptoms that result from that mobility. In general, laxity of ligaments predispose to joint instability, subluxation, and dislocation. Trauma to ligaments, tendons, muscles can occur.
Systemically, hypermobility affects the gastrointestinal system causing functional symptoms like diarrhea and cramping, cardiovascular system like orthostatic tachycardia and bleeding, genitourital system like pelvic pain and bladder dysfunction, and the nervous system like fatigue, brain fog, and anxiety.
Laxity From Upper Crossed/Lower Crossed Syndrome
Laxity occurs from upper crossed/lower crossed syndrome. Most people develop upper crossed/lower crossed syndrome for sitting in a forward flexed position that is a consequence of modern lifestyle. However, this syndrome affects Hypermobility to a greater degree. Staying in prolonged sitting postures causes stiffness to develop in certain areas of the body. This causes the thoracic spine to curve forward and the pelvis to dump forward.
Because the body functions as a fascial chain, stiffness in one part of the body affects mobility in other parts of the body. As parts of the chain stiffens abnormally, other parts of the chain become abnormally more mobile to make up for the increased stiffness in areas that have lost mobility. In Hypermobile connective tissue disorders, because tissue is more distensible and hyper-responsive, a greater degree of microtrauma occurs from too much motion in areas that should be stable.
Laxity From Proprioceptive Disruption
Laxity occurs from impaired proprioception. Proprioception is the sense of the relative position of parts of the body and how much effort is needed for movement and control of the body. Proprioception is provided by the mechanoreceptors that are located within the fascia. Proprioception is also dependent on the architecture of the fascia. In Hypermobile connective tissue disorders, the fascia surrounding the mechanoreceptors are disrupted resulting in impairment of proprioception and inability for the body to know where the joint range of motion stops. This impairment leads to microtrauma as well as traumatic dislocation.
How can you get more answers?
Dr. Wang can work with you to figure things out. Dr. Wang will help you work with your fascia and use motor control exercises to retrain proprioception. Dr. Wang uses Prolotherapy to strengthen tendons and ligaments to help stabilize areas that have too much laxity.