What Are The Types of EDS?

There are six defined types of EDS, as well as a number of mutations identified as EDS that fall outside the current system. The major types of EDS are classified according to the signs and symptoms that are manifested. Each type of EDS is a distinct disorder that "runs true" in a family. An individual with Vascular Type EDS will not have a child with Classical Type EDS.

There are six major types of EDS. The different types of EDS are classified according to their manifestations of signs and symptoms.
Classical type (formerly types I and II) EDS This type affects about 1 in 10,000 to 20,000 people. Signs and symptoms include:

Loose joints
Highly elastic, velvety skin
Fragile skin that bruises or tears easily
Redundant skin folds, such as on the eyelids
Slow and poor wound healing leading to wide scarring
Noncancerous fibrous growths on pressure areas, such as elbows and knees; fatty growths on the shins and forearms
Muscle fatigue and pain
Heart valve problems (mitral valve prolape and aortic root dilation)

Hypermobility type (formerly type III) EDS This type affects approximately 1 in 10,000 to 15,000 people. Signs and symptoms include:

Loose, unstable joints with many dislocations
Easy bruising
Muscle fatigue and pain
Chronic degenerative joint disease.
Advanced premature osteoarthritis with chronic pain.
Heart valve problems (mitral valve prolapse and aortic root dilation)

Vascular type (formerly type IV):This type of EDS is rare, but it's one of the most serious. It affects an estimated 1 in 100,000 to 200,000 people. Signs and symptoms include:

Fragile blood vessels and organs that are prone to tearing (rupture)
Thin, translucent skin that bruises easily
Characteristic facial appearance, including protruding eyes, thin nose and lips, sunken cheeks and small chin
Collapsed lung (pneumothorax)
Heart valve problems (mitral valve prolapse and others)

This information is from Mayo Clinic's article on Ehlers-Danlos Syndrome.

Hypermobility Type

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.

Classical Type

Marked skin hyperextensibility (stretchy) with widened atrophic scars and joint hypermobility are found in the Classical Type of EDS. The skin manifestations range in severity from mild to severe. The skin is smooth and velvety along with evidence of fragility and a tendency to bruise easily. Examples of tissue extensibility and fragility include hiatal hernia, anal prolapse in childhood and cervical insufficiency. Hernias may be a post-operative complication. Scars are found mostly over pressure points such as the knees, elbows, forehead, and chin. Molluscoid pseudo tumors (calcified hematomas) associated with scars are frequently found over pressure points such as the elbows, and spheroids (fat containing cysts) are usually found the on the forearms and shins.

Complications of joint hypermobility include sprains, dislocations/subluxations and pes planus (flat foot) to name a few. Recurrent joint subluxations are common in the shoulder, patella and temporomandibular joints. Muscle hypotonia and delayed gross motor development may also be evident.

The Vascular Type

Vascular Type is generally regarded as the most serious form of EDS due to the possibility of arterial or organ rupture. The skin is usually thin and translucent with veins being seen through the skin, which is most apparent over the chest and abdomen. There are certain facial characteristics present in some affected individuals. These manifestations include large eyes, thin nose, lobeless ears, short stature and thin scalp hair. Also evident is a decrease in subcutaneous tissue, particularly in the face and extremities. Minor trauma can lead to extensive bruising.

Arterial/intestinal/uterine fragility or rupture commonly arise in this type of EDS. Spontaneous arterial rupture has a peak incidence in the third or fourth decade of life, but may occur earlier. Midsize arteries are commonly involved. Arterial rupture is the most common cause of sudden death. Acute diffuse or localized abdominal or flank pain is a common presentation of arterial or intestinal rupture. Life expectancy is shortened with a majority of individuals living only into their forties. Pregnancies may be complicated by intra-partum uterine rupture and pre- and postpartum arterial bleeding. Treatments are available which may help extend life, and surgical interventions are improving.

Joint hypermobility is usually limited to the digits. Tendon and muscle rupture can occur. Talipes equinovarus (clubfoot) is frequently seen at birth. Other manifestations that may be found in the Vascular Type include: acrogeria (premature aging of the skin of the hands and feet); early onset varicose veins; arteriovenous fistula (an opening between an artery and vein), carotid-cavernous fistula; pneumothorax (collapse of a lung) /pneumohemothorax (collapse of a lung with a collection of air or gas and blood); gingival recession and complications during and after surgery (i.e. wound dehiscence).

The Vascular Type of EDS is caused by structural defects in the proa1(III) chain of collagen type III encodes by COL3A1. This type of EDS is inherited in an autosomal dominant manner. A skin biopsy can diagnose this type of EDS.

Kyphoscoliosis (Formerly EDS Type VI)

Generalized joint laxity and severe muscle hypotonia (weak muscle tone) at birth are seen in this type of EDS. The muscular hypotonia can be very pronounced and leads to delayed gross motor development. Individuals with the Kyphoscoliosis Type exhibit scoliosis at birth that is progressive. The phenotype is most often severe, frequently resulting in the loss of ambulation in the second or third decade. Scleral fragility may lead to rupture of the ocular globe after minor trauma.

Tissue fragility including atrophic scars and easy bruising may be seen in the Kyphoscoliosis Type. Spontaneous arterial rupture can occur. Other findings may include: marfanoid habitus (Marfan-like features); micro cornea (abnormally small cornea); and radiologically considerable osteopenia (diminished amount of bone tissue).

Kyphoscoliosis Type EDS is the result of a deficiency of lysylhydroxylase (PLOD), which is a collagen-modifying enzyme. This type of EDS is inherited in an autosomal recessive manner. Kyphoscoliosis Type can be diagnosed through a urine test.

Arthrochalasia (Formerly EDS Type VII A&B)

Congenital hip dislocation has been present in all biochemically proven individuals with this type of EDS. Individuals often have severe generalized joint hypermobility with recurrent subluxations. Other manifestations of this type may include: skin hyperextensibility with easy bruising; tissue fragility including atrophic scars; muscle hypotonia; kyphoscoliosis; and radiologically mild osteopenia.

The Arthrochalasia Type is caused by mutations leading to deficient processing of the amino-terminal end of proa1(I) [type A] or proa2(I)[type B] chains of collagen type I. It is inherited in an autosomal dominant manner. A skin biopsy can also diagnose this type of EDS

Dermatosparaxis (Formerly EDS Type VIIC)

Individuals with Dermatosparaxis Type EDS have severe skin fragility and substantial bruising. Wound healing is not impaired and the scars are not atrophic. The skin texture is soft and doughy. Sagging, redundant skin is evident. The redundancy of facial skin results in an appearance resembling cutis laxa. Large hernias (umbilical, inguinal) may also be seen. The number of patients reported with this type of EDS is small.

Dermatosparaxis Type EDS is caused by a deficiency of procollagenI N-terminal peptidase. It is inherited in an autosomal recessive manner. A skin biopsy can diagnose this type of EDS.

Other Types

The previous EDS Type V (X-linked) had been described in a single family. It is a rare variant and the molecular basis of which remains unknown.

The previous EDS Type VIII is similar to the Classical Type, except that in addition it presents with periodontal friability. The existence of this syndrome as an autonomous entity remains uncertain.

The EDS Type IX was previously redefined as "Occipital Horn syndrome", an X-linked recessive condition allelic to Menkes syndrome. This was previously removed from the EDS classification.

The previous EDS Type X has been described in only one family.

The EDS Type XI termed "Familial Joint Hypermobility syndrome" was previously removed from the EDS classification. Its relationship to the EDS is not yet defined, and it may be a mild variant of Hypermobility Type.

Forms of EDS within this unclassified category may present with soft, mildly stretchable skin, shortened bones, chronic diarrhea, joint hypermobility and dislocation, bladder rupture, or poor wound healing. Inheritance patterns within this group include X-linked recessive, autosomal dominant and autosomal recessive. Examples of these syndromes include: Beasley-Cohen Type, Progeroid form - B4GALT7, Friedman-Harrod Type, Tenascin-X deficiency - TNXB and Musculocontractural type - CHST14.