What is Ehlers-Danlos syndrome?
Ehlers-Danlos syndrome (EDS) is the name given to a group of inherited disorders that involve a genetic defect in collagen and connective tissue synthesis and structure. This results in fragile and hyperelastic skin, unstable and hyperextensible (hypermobile) joints, and fragile tissue and blood vessels.
EDS may occur in males and females of all races and usually first appears in young adults.
Types of Ehlers-Danlos syndrome
There are six subtypes of EDS, classified according to the clinical features. Each is a distinct disorder that ‘runs true’ in a family. This means that members of a single family affected by EDS will share the same features of it. Some cases do not fit neatly into a known type of EDS and in many situations a patient may show features of more than one type.
Subtypes of EDS [view table in a new window]
What causes Ehlers-Danlos syndrome?
Collagen is one of the main building blocks of the body. It is a protein that is widely found in all organs of the body. Several types of collagen exist, each with differing properties. Collagen can provide strength and firm support, be elastic to allow movement, or it can be used to bind things together.
A genetic defect causes reduced amounts of collagen, disorganisation of collagen that is usually organised into bundles, and alterations in the size and shape of collagen. The type of EDS a patient has depends on how collagen metabolism has been affected. For example vascular EDS is caused by decreased or absent synthesis of type III collagen.
What are the signs and symptoms?
Signs and symptoms differ in type and severity between the different types of EDS.
- Skin hyperextensibility: it is easy to pull the skin away from the body and once released it retracts to its original state.
- Skin fragility: the skin easily splits. Wounds heal very slowly resulting in gaping fish-mouth or cigarette paper scars.
- Epicanthic folds: skin folds between the eyes make the bridge of the nose appear wide.
- Molluscoid pseudotumours: small spongy lumps 2-3cm in diameter over pressure points such as the knees and elbows.
- Nodules: small, firm lumps just below the skin surface on the arms and shins.
- Hypermobility: joints bend more than usual. The fingers are most often affected but all joints can be involved. The joints may dislocate but can be popped back painlessly.
- Bruising and haematomas may arise after trivial injuries.
- Internal collagen defects: heart murmur (mitral valve prolapse) and weakened walls of intestines, arteries and uterus, which may rupture.