Individuals with Ehlers-Danlos syndromes (EDS) have a genetic defect in their connective tissue, the tissue that provides support to many body parts such as the skin, muscles and ligaments. The fragile skin and unstable joints found in patients with EDS are the result of faulty or reduced amounts of collagen. Collagen is a protein, which acts as a "glue" in the body, adding strength and elasticity to connective tissue.

EDS is a heterogeneous group of heritable connective tissue disorders, characterized by articular (joint) hypermobility, skin extensibility and tissue fragility. There are six major types of EDS. The different types of EDS are classified according to their manifestations of signs and symptoms. Each type of EDS is defined as a distinct disorder that "runs true" in a family. This means that an individual with Vascular Type EDS will not have a child with Classical Type EDS.

What are the symptoms of EDS?
Clinical manifestations of EDS are most often joint and skin related and may include:
    Collagen is a strong, fibrous protein that lends strength and elasticity to connective tissues such as the skin, tendons, organ walls, cartilage, and blood vessels. Each of these connective tissues requires collagen tailored to meet its specific purposes. The many roles of collagen are reflected in the number of genes dedicated to its production. There are at least 28 genes in humans that encode at least 19 different types of collagen. Mutations in these genes can affect basic construction as well as the fine-tuned processing of the collagen.
Each type of EDS is defined as a distinct problem in making or using one of the types of collagen. Collagen is what the body uses to provide strength and elasticity to tissue; normal collagen is a strong protein that allows tissue to be stretched but not beyond its limit, and then safely returns that tissue to normal. Collagen is found throughout the body, and EDS are a structural problem. An analogy: If one builds a house with bad materials, with cheap nails or only half the wood required, problems will arise. Some problems are more likely to show up than others, but because the bad or missing materials are everywhere and not necessarily visible, one can be surprised where some problems occur.
EDS is a group of inherited connective tissue disorders that usually affects the skin, ligaments, joints, and blood vessels. Classification of EDS types was revised in 1997. The new classification involves categorizing the different forms of EDS into six major sub-types, including classical, hypermobility, vascular, kyphoscoliosis, arthrochalasia, and dermatosparaxis, and a collection of rare or poorly defined varieties. This new classification is simpler than the previous classification system and is primarily based on descriptions of the actual symptoms.
Miscellaneous/Less Common Chronic, early onset, debilitating musculoskeletal pain (usually associated with the Hypermobility Type); arterial/intestinal/uterine fragility or rupture (usually associated with the Vascular Type); scoliosis at birth and scleral fragility (associated with the Kyphoscoliosis Type); poor muscle tone (associated with the Arthrochalasia Type); mitral valve prolapse; and gum disease.

It is much the same thing with EDS and collagen. The collagen with which a person with EDS is built is not structured the way it should be, or only part of it is produced. With a badly built or processed collagen, the tissue that relies on it can be pulled beyond normal limits and thus be damaged. Collagen is the most abundant protein in the body and types of collagen can be found almost anywhere: in skin, muscles, tendons and ligaments, blood vessels, organs, gums, eyes, and so on.

The problems resulting from one’s body being built out of a protein that behaves unreliably can be widespread, in a wide range of severities, and show up in places that seem unrelated until the underlying connection to EDS is recognized.

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.

How is EDS diagnosed?
In 1997, a nosology was written at the Villefranche International Conference that refined the types of EDS into the current six major types. Each type has a set of major diagnostic criteria and of minor diagnostic criteria. Traditional diagnosis of EDS consists of family history and clinical evaluation to assess the diagnostic criteria. Genetic testing is available for most types of EDS, although not for the most common type, Hypermobility. The tests vary in accuracy; in most instances genetic testing should be used conservatively to confirm an EDS type diagnosis rather than to rule one out. 

How prevalent is EDS?
At this time, research statistics of EDS show the prevalence as 1 in 2,500 to 1 in 5,000 people. Recent clinical experience suggests EDS is more common. The condition is known to affect both males and females of all racial and ethnic backgrounds.

How is EDS inherited?
The two known inheritance patterns for EDS include autosomal dominant and autosomal recessive. Specifics regarding genetic inheritance may be found by following the link below. Regardless of the inheritance pattern, we have no choice in which genes we pass on to our children.

What is the prognosis of someone with EDS?
The prognosis depends on the type of EDS and the individual. Life expectancy can be shortened for those with the Vascular Type of EDS due to the possibility of organ and vessel rupture. Life expectancy is usually not affected in the other types. There can be a wide or narrow range of severity within a family, but each person’s case of EDS will be unique. While there is no cure for EDS, there is treatment for symptoms, and there are preventative measures that are helpful for most.

What can I do now?
EDNF members are sharing information online and learning from each other in ways that were impossible not very long ago. Visit EDNF's Facebook page, the EDNF Inspire Online Community, or look through the various EDNF publications available through the EDS Guides menu on the left hand side of this page.