少见的病种

What is Ehlers-Danlos syndrome?

Ehlers-Danlos syndromes is a group of disorders which share common features including easy bruising, joint hypermobility (loose joints), skin that stretches easily (skin hyperelasticity or laxity), and weakness of tissues.

The Ehlers-Danlos syndromes are inherited in the genes that are passed from parents to offspring. They are categorized according to the form of genetic transmission into different types with many features differing between patients in any given type. The fragile skin and loose joints is often a result of abnormal genes that produce abnormal proteins that form an inherited frailty of collagen (the normal protein "glue" of our tissues).

In 2001, researchers discovered a new form of Ehlers-Danlos syndrome that is caused by an inherited abnormality in a protein other than collagen that also normally plays a role in binding together the cells of our tissues (including the skin, tendons, muscle, and blood vessels). Abnormalities in this protein, called tenascin, also lead to a form of Ehlers-Danlos syndrome. Researchers suspect that tenascin could play a role in regulating the normal distribution of collagen in the connective tissues of the body.

The diagnosis of Ehlers-Danlos syndromes is based upon the clinical findings of the patient and the family history. For some types of Ehlers-Danlos syndrome a skin biopsy to determine the chemical makeup of the connective tissue can help to suggest the diagnosis.

What are the types of Ehlers-Danlos syndromes?

Classical Type

(formerly Types I & II)

Marked joint hypermobility, skin hyperextensibility (laxity), and fragility are characteristic of the classic type of Ehlers-Danlos syndrome. The smooth, velvety skin is fragile and tears or bruises easily with minor trauma. Joint dislocations and scoliosis are common. Joint instability can lead to sprains and strains. This classical type is inherited as an autosomal dominant genetic trait (directly passed on from one parent to child).

Hypermobility Type

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Joint hypermobility is the major manifestation of this form of Ehlers-Danlos syndrome. Any joint can be affected and dislocations are frequent. Inherited as an autosomal dominant genetic trait.

Vascular Type

(formerly Type IV, the arterial form)

In this form of Ehlers-Danlos syndrome, spontaneous rupture of arteries and bowel is a serious manifestation that can lead to death. Clubfoot can be present at birth. Skin laxity is of varying degrees. Veins can be very visible through the skin. It is inherited as an autosomal dominant (directly passed on from one parent to child) and recessive (not seen in family members or only in one generation of members of the same family) genetic trait.

Kyphoscoliosis Type

(formerly Type VI)

Fragile globe of the eyes, significant skin and joint laxity, and severe curvature of the spine (scoliosis) are typical features. It is inherited as an autosomal recessive (not seen in family members or only in one generation of members of the same family).

Arthrochalsia Type

(formerly type VIIB, arthrochalasis multiplex congenita)

Patients are short in height and severely affected by joint laxity and dislocations. Skin involvement is variable. Autosomal dominant and recessive inheritance is possible. A skin biopsy can be used to diagnose this disorder.

Dermatosparaxis Type

(formerly Type VIIC)

Patients have severely fragile skin that is soft and doughy with sagging and folding. This rare form of Ehlers-Danlos syndrome can be diagnosed with a skin biopsy.

Tenascin-X Deficient Type

Joint hypermobility, hyperelastic skin, and fragile tissue are seen. Lacking multiple shrinking (atrophied) scars in the skin that is often seen in classic Ehlers-Danlos. Inherited as an autosomal recessive genetic trait (not seen in family members or only in one generation of members of the same family).

Other rare variant types have been reported in single families

How are the Ehlers-Danlos syndromes treated?

The Ehlers-Danlos syndromes are treated according to what particular manifestations present in a given individual.

Skin protection (from injury of trauma and sun, etc.) is critical. Wounds must be tended to with great care and infections treated and prevented. Suturing can be difficult as the skin can be extremely fragile.

Joint injury must be avoided. Occasionally, bracing may be necessary to maintain joint stability. Exercises that strengthen the muscles that support the joints can help to minimize joint injury. Contact sports and activities involving joint impact should be avoided.