What is cEDS?

What Are Connective Tissue and Collagen?



To understand Ehlers-Danlos syndrome, it helps to first understand connective tissue and collagen.

What is connective tissue?

Connective tissue is found throughout almost the entire body. It helps support, connect, protect and hold our bodies together.

It is found in and around many different structures, including:

• Skin
• Joints and ligaments
• Tendons
• Muscles
• Bones
• Blood vessels
• Internal organs
• 
  

A useful way to imagine connective tissue is as part of the body’s framework and support system. It helps tissues stay strong while also allowing them to move, stretch and withstand everyday stresses.

What is collagen?

Collagen is one of the main proteins found within connective tissue. There are several different types of collagen, and they have different roles throughout the body.

Think of collagen as some of the body’s supporting fibres. These fibres help give tissues their strength, structure and stability.

In classical Ehlers-Danlos syndrome (cEDS), the problem most commonly involves type V collagen.

Most people with cEDS have a genetic change in either the COL5A1 or COL5A2 gene. These genes contain instructions that the body uses when producing type V collagen.

When those instructions are altered, collagen may not be produced or organised in the usual way. This affects the structure and strength of connective tissues throughout the body.

Why can one collagen problem affect so much of the body?

Because connective tissue is found almost everywhere.

This is why cEDS isn’t simply a condition of the skin or joints. The effects of altered connective tissue can appear in different ways and in different parts of the body.

For example, it can contribute to stretchy and fragile skin, unusual scarring, easy bruising, joint hypermobility and instability, dislocations, musculoskeletal problems and difficulties with wound healing.

Not everybody with cEDS will experience exactly the same symptoms or to the same degree. Even people within the same family can be affected differently.

That is one of the important things to understand about cEDS:

Collagen may be microscopic, but connective tissue is everywhere, so its effects can be anything but small.

What Causes Classical Ehlers-Danlos Syndrome?

Classical Ehlers-Danlos syndrome (cEDS) is a genetic condition, which means it is caused by a change, also known as a pathogenic variant, in a gene.

Genes are a little like sets of biological instructions. They tell our bodies how to make the proteins needed for our bodies to develop, function and repair themselves.

Which genes are associated with cEDS?

In the majority of people with cEDS, the condition is caused by a genetic change affecting either the COL5A1 or COL5A2 gene.

These genes provide instructions involved in making type V collagen, which plays an important role in the structure and organisation of connective tissue.

More rarely, certain changes in the COL1A1 gene can cause a classical EDS phenotype.

When one of these genes is affected, the body’s collagen doesn’t function or organise itself in quite the way it should. Because collagen and connective tissue are found throughout the body, the effects can appear in many different places.

Is cEDS inherited?

cEDS is usually inherited in an autosomal dominant pattern.

This means that a person only needs one altered copy of the relevant gene to have the condition.

If someone with cEDS has children, each child generally has a 50% chance of inheriting the genetic variantresponsible for the condition. This chance applies separately to each pregnancy.

However, not everybody diagnosed with cEDS has a parent who also has the condition.

Sometimes the genetic change happens for the first time in that individual. This is known as a de novo variant. That person can then potentially pass the variant on to their own children.

Does having the same genetic change mean having the same symptoms?

Not necessarily.

cEDS can vary considerably from one person to another. Even members of the same family who share the same genetic variant may experience different symptoms or levels of severity.

Genetics provides part of the explanation for why cEDS happens, but it doesn’t provide a perfect blueprint for exactly how the condition will affect an individual throughout their life.



Most importantly, cEDS isn’t something you develop because of something you did.

A person with cEDS is born with the genetic change that causes it. It isn’t caused by lifestyle, diet, exercise or anything a person or their family did wrong.

It is quite literally written into the body’s biological instructions from the very beginning.

Signs and Symptoms of Classical Ehlers-Danlos Syndrome

Classical Ehlers-Danlos syndrome (cEDS) can affect people in many different ways. Some features are considered characteristic of the condition, while others may occur in some people but not others.

The severity can also vary considerably. Two people with cEDS, even members of the same family, may have very different experiences.

The Hallmark Features of cEDS

Three of the features most strongly associated with classical EDS are:

Skin hyperextensibility
The skin can stretch further than would usually be expected and then return to its normal position.

Atrophic scarring
Wounds may heal with characteristic thin, widened or sunken scars. These are particularly common over areas exposed to repeated knocks or pressure, such as the knees, elbows, shins and forehead.

Generalised joint hypermobility
Many joints may move beyond the usual range. Hypermobility can also come with joint instability and may contribute to sprains, subluxations and dislocations.

But cEDS can involve considerably more than these three features.

Skin and Wound Healing

People with cEDS may experience:

• Soft or unusually velvety skin
• Hyperextensible or stretchy skin
• Fragile skin that can split or tear relatively easily
• Delayed or difficult wound healing
• Characteristic atrophic scarring
• Widening of scars over time
• Easy bruising
• Molluscoid pseudotumours, which are fleshy lesions that can develop around areas exposed to repeated pressure, particularly the elbows and knees
• Subcutaneous spheroids, which are small, firm lumps that can develop beneath the skin

Because the skin can be fragile, injuries and surgical wounds may sometimes require particular care.

Joints and Musculoskeletal Problems

Joint hypermobility is one of the major features of cEDS, but being hypermobile doesn’t necessarily mean joints work better.

Some people experience:

• Generalised joint hypermobility
• Joint instability
• Recurrent sprains and strains
• Subluxations, where a joint partially moves out of position
• Dislocations, where a joint moves completely out of position
• Joint or musculoskeletal pain
• Problems resulting from repeated joint injuries
• Reduced muscle tone, particularly during childhood
• Muscle weakness or fatigue

Joint hypermobility can also become less obvious with age, injury, surgery or increasing stiffness. Someone therefore doesn’t necessarily stop having cEDS simply because they are no longer as flexible as they once were.

Bruising

Easy bruising is common in cEDS.

Bruises may appear following relatively minor knocks and can sometimes seem disproportionate to the injury that caused them.

This happens because connective tissue also provides support to small blood vessels and surrounding tissues.

Other Recognised Features

Other features associated with cEDS can include:

• Hernias
• Prolapse
• Flat feet
• Certain characteristic facial features, particularly in some children
• Complications associated with joint instability and repeated injuries

There are also rarer complications associated with cEDS. These should be considered individually rather than assuming that everybody with the condition will develop them.

Everyone’s cEDS Is Different

One of the most important things to remember is that cEDS exists on a spectrum.

A person doesn’t need to experience every possible feature, and symptoms can change throughout life.

Some effects are immediately visible, such as scars or bruising. Others, including pain, instability and the effort involved in protecting vulnerable joints and tissues, may be completely invisible to somebody looking from the outside.

cEDS is much more than being “bendy” or having stretchy skin. It is a lifelong connective tissue disorder, and its impact can reach into many different aspects of everyday life.