Types of EDS

Types of EDS

Ehlers-Danlos Syndrome, commonly abbreviated as EDS, is a group of genetically inherited connective tissue disorders. Connective tissues are responsible for supporting and structuring the blood vessels, skin, organs and bones. EDS has been thought to alter the biological production of collagen (the most abundant protein) either directly or indirectly which results in multi-systematic symptoms. Any kind of defect in the structure, processing or production of collagen in the body can potentially cause EDS.

Understanding Ehlers-Danlos Syndrome

What is Ehlers-Danlos Syndrome?

Ehlers-Danlos Syndrome, commonly abbreviated as EDS, is a group of genetically inherited connective tissue disorders. Connective tissues are responsible for supporting and structuring the blood vessels, skin, organs and bones. EDS has been thought to alter the biological production of collagen (the most abundant protein) either directly or indirectly which results in multi-systematic symptoms. Any kind of defect in the structure, processing or production of collagen in the body can potentially cause EDS.

The symptoms of EDS vary from mildly loose joints to life-threatening complications. Since the symptoms of EDS are not very exceptional, it is sometimes misdiagnosed with depression, hypochondriasis, chronic fatigue syndrome and other similr conditions. There are six major types of Ehlers-Danlos Syndrome. Each of these types has a certain physical trait which helps in diagnosis. There are physical characteristics which are common to all types of Ehlers-Danlos Syndrome such as hypermobile joints (i.e. movement of joints in an amount greater than expected) and symptoms involving skin such as saggy, stretchy, soft, too thin, easy wounding, easy bruising, poor wound healing etc.

What are the different types of Ehlers-Danlos Syndrome?

There are major six types of EDS:
  • Arthrochalasia
  • Classic
  • Dermatosparaxis
  • Hypermobility
  • Kyphoscoliosis
  • Vascular

Each type of EDS shows its effects on different areas in the body. However, hypermobility is the common symptom of all types of EDS. In fact, the classic and hypermobility types of EDS are the most common. These six types of EDS are defined in accordance to the signs and symptoms that are witnessed in case of each. Each type of EDS is a distinct disorder that runs true in a family. This means that an individual with a classic type of EDS will not have a child with a vascular type of EDS. This syndrome has been known to affect men and women of all races and ethnic backgrounds.

  • ADAMTS2
  • COL1A1
  • COL1A2
  • COL3A1
  • COL5A1
  • COL6A2
  • PLOD1
  • TNXB

These genes work in correspondence to collagen and any defect in these genes weakens the process and formation of collagen in the body.
What are the symptoms of EDS?

The clinical manifestations of EDS are most often related to skin and joints in the body.

Joints hypermobility, loose or unstable joints which are prone to regular dislocations, joint pain, early onset of osteoarthritis and hyperextensible joints are some of the common symptoms relating to joints.

Skin – the manifestation of EDS in the skin include variable skin hyper-extensibility, soft velvety-like skin, fragile skin that is prone to tearing or bruising, slow wound healing, severe scarring etc.

Miscellaneous – some symptoms occur in miscellaneous parts of the body but still contribute to EDS. These include arterial, intestinal or uterine fragility or rupture; chronic, early onset, unbearable musculoskeletal pain; poor muscle tone; gum disease; scoliosis at birth and scleral fragility etc.

Each type of Ehlers-Danlos Syndrome displays a distinct problem in relation to the collagen. Collagen is the protein used by the body to provide strength and elasticity to the tissues. It allows tissues to stretch up to a limit and then return to the normal position. Collagen is found throughout the body and EDS is a structural problem. This means that the collagen present in an individual diagnosed with EDS is not structured as it should be, or it is produced partially. This badly processed or partially produced collagen allows the tissue to be stretched beyond its limits and thus be damaged. Since the symptoms of EDS are more or less the same, there are types that have distinctively distinguished symptoms.

How is EDS diagnosed?

EDS is diagnosed following a series of tests. These tests may include genetic tests, echochardiogram and skin biopsy. A blood sample is taken from your arm and tested for mutations in certain genes. A DNA test can confirm if the genes are present in the embryo as well. A skin biopsy is performed to check for signs of abnormalities in the production of collagen. A small sample of your skin is removed and diagnosed under a microscope. An echochardiogram uses sound waves to create moving images of the heart and the doctor examines it for any abnormalities.
Each type of EDS has a set of major and minor diagnostic criteria. Conventional diagnosis of EDS consists of family history and clinical evaluation to assess the diagnostic criteria. Except for hypermobility, genetic testing is available for all types of EDS.

How is EDS treated?

  • Surgery to repair damaged joints
  • Physical therapy for those who experience joint and muscle instability
  • Drugs to minimize pain

There are also some additional treatment options available but they depend on the severity of pain you experience.
An individual can take the following steps to prevent injuries and protect their joints:

  • Avoid lifting weights
  • Avoid contact sports
  • Use sunscreen to protect the skin
  • Avoid harsh soaps that may cause allergic reaction or over-dry the skin.
  • Use assistive devices to minimize pressure on your joints.
  • Put adequate padding on your child while teaching them how to walk or ride a bike.

What are some potential complications of EDS?

  • Chronic Joint Pain
  • Joint Dislocation
  • Slow healing of wounds, leading to prominent scarring
  • Surgical wounds that heal slowly
  • Early-onset arthritis

The prognosis of EDS varies from individual to individual and the type of EDS they have. For the vascular type of EDS, the life expectancy may be shortened owing to the potential organ and vessel rupture. There is no cure for Ehlers-Danlos Syndrome but there are treatment for its symptoms and some preventive measures which have proven to be quite helpful.

Classical Type (formerly types I and II)

andrea-self-portraitMarked skin hyperextensibility (stretchy) with widened atrophic scars and joint hypermobility are found in the Classical Type of EDS. The skin manifestations range in severity from mild to severe. The skin is smooth and velvety along with evidence of fragility and a tendency to bruise easily. Examples of tissue extensibility and fragility include hiatal hernia, anal prolapse in childhood and cervical insufficiency. Hernias may be a post-operative complication. Scars are found mostly over pressure points such as the knees, elbows, forehead, and chin. Molluscoid pseudo tumors (calcified hematomas) associated with scars are frequently found over pressure points such as the elbows, and spheroids (fat containing cysts) are usually found the on the forearms and shins. Complications of joint hypermobility include sprains, dislocations/subluxations and pes planus (flat foot) to name a few. Recurrent joint subluxations are common in the shoulder, patella and temporomandibular joints. Muscle hypotonia and delayed gross motor development may also be evident. Clinical Testing – Abnormal electrophoretic mobility of the proa1(V) or proa2(V) chains of collagen type V has been detected in several but not all families with the Classical Type, although recent work may have brought molecular diagnosis rate to over 90%. The Classical Type of EDS is inherited in an autosomal dominant manner.

Hypermobility Type (formerly type III)

andrea-self-portraitJoint hypermobility is the dominant clinical manifestation. Generalized joint hypermobility that affects large (elbows, knees) and small (fingers, toes) joints is evident in the Hypermobility Type. Recurring joint subluxations and dislocations are common occurrences. Certain joints, such as the shoulder, patella and temporomandibular joint dislocate frequently. The skin involvement (smooth velvety skin with or without hyperextensibility) as well as bruising tendencies in the Hypermobility Type are present but quite variable in severity. Chronic pain is a well-established and cardinal manifestation of Hypermobility EDS and it is common for pain to be out of proportion to physical and radiological findings. The origin of the pain is not clearly understood, but some of the likely causes include muscle spasm (tender points are sometimes present) and degenerative arthritis; neuropathic pain is also common. To date, there is no distinctive biochemical collagen finding identified for the majority of Hypermobility cases. The Hypermobility Type of EDS is inherited in an autosomal dominant manner.

Vascular Type (formerly type IV)

andrea-self-portraitVascular Type is generally regarded as the most serious form of EDS due to the possibility of arterial or organ rupture. The skin is usually thin and translucent with veins being seen through the skin, which is most apparent over the chest and abdomen. There are certain facial characteristics present in some affected individuals. These manifestations include large eyes, thin nose, lobeless ears, short stature and thin scalp hair. Also evident is a decrease in subcutaneous tissue, particularly in the face and extremities. 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. Acute diffuse or localized abdominal or flank pain is a common presentation of arterial or intestinal rupture. Life expectancy is shortened with a majority of individuals living only into their forties. Pregnancies may be complicated by intra-partum uterine rupture and pre- and postpartum arterial bleeding. Treatments are available which may help extend life, and surgical interventions are improving. Joint hypermobility is usually limited to the digits. Tendon and muscle rupture can occur. Talipes equinovarus (clubfoot) is frequently seen at birth. Other manifestations that may be found in the Vascular Type include: acrogeria (premature aging of the skin of the hands and feet); early onset varicose veins; arteriovenous fistula (an opening between an artery and vein), carotid-cavernous fistula; pneumothorax (collapse of a lung) /pneumohemothorax (collapse of a lung with a collection of air or gas and blood); gingival recession and complications during and after surgery (i.e. wound dehiscence). The Vascular Type of EDS is caused by structural defects in the proa1(III) chain of collagen type III encodes by COL3A1. This type of EDS is inherited in an autosomal dominant manner. A skin biopsy can diagnose this type of EDS.

Kyphoscoliosis Type (Formerly EDS Type VIA)

andrea-self-portraitGeneralized joint laxity and severe muscle hypotonia (weak muscle tone) at birth are seen in this type of EDS. The muscular hypotonia can be very pronounced and leads to delayed gross motor development. Individuals with the Kyphoscoliosis Type exhibit scoliosis at birth that 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 in the Kyphoscoliosis Type. Spontaneous arterial rupture can occur. Other findings may include: marfanoid habitus (Marfan-like features); micro cornea (abnormally small cornea); and radiologically considerable osteopenia (diminished amount of bone tissue). Kyphoscoliosis Type EDS is the result of a deficiency of lysylhydroxylase (PLOD), which is a collagen-modifying enzyme. This type of EDS is inherited in an autosomal recessive manner. Kyphoscoliosis Type can be diagnosed through a urine test.

Arthrochalasia Type (Formerly EDS Type VIIA & VIIB)

andrea-self-portraitCongenital hip dislocation has been present in all biochemically proven individuals with this type of EDS. Individuals often have severe generalized joint hypermobility with recurrent subluxations. Other manifestations of this type may include: skin hyperextensibility with easy bruising; tissue fragility including atrophic scars; muscle hypotonia; kyphoscoliosis; and radiologically mild osteopenia. The Arthrochalasia Type is caused by mutations leading to deficient processing of the amino-terminal end of proa1(I) [type A] or proa2(I)[type B] chains of collagen type I. It is inherited in an autosomal dominant manner. A skin biopsy can also diagnose this type of EDS

Dermatosparaxis Type (Formerly EDS Type VIIC)

andrea-self-portraitIndividuals with Dermatosparaxis Type EDS have severe skin fragility and substantial bruising. Wound healing is not impaired and the scars are not atrophic. The 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. The number of patients reported with this type of EDS is small.
Dermatosparaxis Type EDS is caused by a deficiency of procollagenI N-terminal peptidase. It is inherited in an autosomal recessive manner. A skin biopsy can diagnose this type of EDS.