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Types of Ehlers-Danlos Syndrome
Types of Ehlers-Danlos Syndrome
Reprinted with Permission from the
Canadian Ehlers-Danlos Association (CEDA)
Ehlers-Danlos Syndrome (EDS) is a
heterogeneous group of heritable connective tissue disorders characterized
by articular hypermobility, skin extensibility and tissue fragility. There
are six major types of EDS. The different types of EDS are classified
according distinct features.
Marked skin hyperextensibility with
widened atrophic scars and joint hypermobility are found. The skin
manifestations range in severity from mild to severe expression. The skin is
smooth and velvety with evidence of tissue fragility including hiatal
hernia, anal prolapse in childhood, and cervical insufficiency. Hernias may
be a post-operative complication. Also evident are molluscoid pseudotumors
frequently found over pressure points and subcutaneous spheroids which are
mobile and palpable on the forearms and shins.
Complications of joint hypermobility
include sprains, dislocations/subluxations and pes planus. Recurrent
subluxations are common in the shoulder, patella and temporomandibular
joints. Muscle hypotonia and/or delayed gross motor development may be
evident.
Abnormal electrophoretic mobility of the
proa 1(V) or proa 2(V) chains of collagen type V has been detected.
Inheritance: Autosomal dominant.
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information on Classical type EDS.
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Skin involvement (hyperextensible and/or
smooth, velvety skin) as well as bruising tendencies are both variable.
Joint hypermobility is the dominant clinical manifestation. Generalized
joint hypermobility that affects both large and small joints is evident in
Hypermobile Type EDS. Recurring joint dislocations are common occurrences.
Certain joints, such as the shoulder, patella, and temporomandibular joint
dislocate frequently.
Chronic joint and limb pain is a common
complaint among individuals with Hypermobile Type EDS. Skeletal X-rays are
normal. Musculoskeletal pain is early onset, chronic and may be
debilitating. The anatomical distribution is wide, tender points are often
elicited.
To date, researchers have identified no
distinctive biochemical collagen finding. Inheritance: Autosomal dominant.
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Vascular Type
Thin translucent skin reveals the
subcutaneous venous pattern, and is particularly apparent over the chest and
abdomen. Facial appearance is characteristic in some affected individuals. A
decrease in subcutaneous tissue, particularly in the face and extremities is
evident. 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. Life
expectancy is shortened with a majority of individuals.
Joint hypermobility is usually limited to
the digits. Tendon and muscle rupture can occur. Talipes equinovarus is
frequently seen at birth. Other manifestations that may be found include:
acrogeria; early onset varicose veins; arteriovenous, carotid-cavernous
fistula; pneumothorax/pneumohemothorax; gingival recession; complications
during and after surgery.
Vascular Type EDS is caused by structural
defects in the proa` 1 (III) chain of collagen type III encodes by COL3A1.
Inheritance: Autosomal dominant.
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more information on Vascular Type EDS.
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Generalized joint laxity and severe muscle
hypotonia at birth are seen in this type of EDS. Muscular hypotonia can be
very pronounced and leads to delayed gross motor development. Individuals
present with scoliosis at birth. The scoliosis 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. Spontaneous arterial rupture can easily
occur. Other findings may include marfanoid habitus, microcornea, and
radiologically considerable osteopenia.
Kyphoscoliosis Type EDS is the result of a
deficient lysyl hydroxylase (PLOD). Inheritance: Autosomal recessive.
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Congenital hip dislocation is present in
all, as well as severe generalized joint hypermobility with recurrent
subluxations, skin hyperextensibility with easy bruising, tissue fragility
including atrophic scars, muscle hypotonia, kyphoscoliosis, and
radiologically mild osteopenia.
Arthrochalasia Type EDS is caused by
mutations leading to deficient processing of the amino-terminal end of proa
1(I) [type A] or proa 2 (I) [type B] chains of collagen type I. Inheritance:
Autosomal dominant.
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Individuals demonstrate severe skin
fragility and bruising. Wound healing is not impaired and the scars are not
atrophic, 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.
Dermatosparaxis Type EDS is caused by a
deficiency of procollagen I N-terminal peptidase. Inheritance: Autosomal
recessive.
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for information on Dermatosparaxis Type EDS.
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The prognosis of EDS depends on the
specific type. Life expectancy can be shortened with the Vascular Type of
EDS due to the possibility of organ and vessel rupture. Life expectancy in
all other types is normal.
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Beighton, P., De Paepe, A., Steinmann, B.,
Tsipouras, P., & Wenstrup, R. (in press). Ehlers-Danlos Syndrome: Revised
Nosology, Villefranche, 1997. American Journal of Medical Genetics.
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