Ehlers Danlos Syndrome

What is Ehlers Danlos Syndrome?

Ehlers Danlos syndrome or EDS is a group of disorders in the connective tissues that people inherit as a genetic characteristic. The mutation of almost a dozen genes causes the condition and the type of syndrome that a person has depends on the specific gene that has affected.

Some people inherit the genes in an autosomal dominant or recessive manner, while in others it is the result of new mutations during early development. These genes then lead to irregularities in the processing and structure of

Image Source: Dermnetnz.org

collagen. It is essential for skin elasticity, thus causing problems in the connective tissues. However, the intensity in which it manifests itself varies from one individual to another. Joint hypermobility, tissue fragility, hyper skin extensibility, etc. are features of this syndrome.

Types of Ehlers Danlos Syndrome

• Classic
• Classic-like
• Cardiac-valvular
• Vascular
• Hypermobile
• Arthrochalasia
• Dermatosparaxis
• Kyphoscoliotic
• Brittle cornea
• Spondylodysplastic
• Musculocontractural
• Myopathic
• Periodontal

Causes of Ehlers Danlos Syndrome

Classical

• Includes dominant inheritance pattern for mutation of COL5A1 & COL5A2 genes
• COL5A1 conceals the protein pro-alpha1(V)chain & COL5A1 conceals the protein pro-alpha2(V)chain
• ‘Pro’ designation means that an enzyme has to act on the final product which makes the end product active
• Three chains like proteins make up the procollagen
• Extracellular enzymes work on the procollagen resulting in the formation of a mature product
• The final product becomes fibrils of type 1 collagen and also determines the width of the fibrils

Classical-like

• Mutations in the gene TNXB causes classical like EDS
• Gene product is found outside the cell and helps to prevent corruption of the structure in which the collagen is present Image Source: Dermnetnz.org

Cardiac-valvular Types

• Result of mutations in the COL1A2 gene
• Follows an autosomal recessive pattern of inheritance
• COL1A2 encodes pro-alpha2(I)chain
• One pro-alpha2(I)chain and two pro-alpha1(I)chain come together to form type 1 procollagen fibrils

Vascular Type

• Usually, mutations in the COL3A1 gene cause this type of EDS
• Some reports state where two mutant genes affect the individual known as bi-allelic inheritance in medical terms
• COL3A1 encodes pro-alpha1(III)chain, three of these chains come together to form type III procollagen
• Type III collagen assemble to form long thin fibrils
• Strength of this collagen subtype is a result of cross-linking

Hypermobility Type

• There has not been much success in identifying the genes that cause this condition. However, it follows an autosomal dominant inheritance pattern
• A small number of people suffering from this syndrome have a deficiency of tenascin-x, the gene TNXB encodes this protein
• Tenascin-x helps to regulate the stability of the body’s elastic fiber and maintains the incorruptibility of the frame in which the collagen is present Image Source: Dermnetnz.org

Arthrochalasia Type

• Mutations in the COL1A1 and COL1A2 genes cause this type of EDS
• Follows the pattern of autosomal dominant inheritance

Dermatosparaxis Type

• Result of mutations in the gene ADAMTS2
• Modification of collagen happens due to the enzyme that this gene encodes
• Separates short amino acid chains from procollagen molecules to form mature collagen

Kyphoscoliotic Type

• Follows autosomal recessive inheritance
• Mutations in the PLOD1 and FKBP14 genes cause this condition
• Mutations in PLOD1 cause lower activity in enzymes like Procollagen-lysine, 2oxyglucorate 5-deoxygenase 1
• Enzyme is responsible for the conversion of amino acid lysine to hydrolysine (essential for the formation of cross-links between individual collagen chains)
• FKBP14 gene encodes FK506 binding protein-14, but it does not have any specific function

Brittle cornea Syndrome

• Two types of BCS where each follows the autosomal recessive manner of inheritance
• Mutations in the ZNF469 gene causes type 1 BCS, Zinc finger protein, 469 acts as extranuclear regulator for collagen fiber synthesis
• Mutation in the PRDM5 gene causes type 2 BCS and encodes the protein PR/SET domain five which in transcription factor in the regulation of protein synthesis

Spondylodysplastic Type

• Follows autosomal recessive condition
• Mutation of the gene SLC39A13 that encodes protein product solute carrier family, 39 members 13 means of transport zinc to the cells which is essential for healthy function of the connective tissues
• Genetic defects in the B4GALT6 and B4GALT7 genes are attributes of this syndrome

Musculocontractural Type

• Follows autosomal recessive inheritance pattern
• Mutations in two genes – CHST14 & DSE
• Mutation of CHST14 encodes the enzyme carbohydrate sulfotransferase 14 that transfers sulfate groups between molecules
• Gene product dermatan sulfate epimerase helps in production of glycosaminoglycan which fills the gaps in the connective tissues and provides stability

Myopathic type

• May follow either the autosomal dominant or autosomal recessive pattern of inheritance
• Mutation of COL12A1 gene causes this kind of syndrome and it encodes the type XII collagen

Periodontal Type

• Follows the autosomal dominant pattern of inheritance
• Mutations in the genes C1R and C1S cause this syndrome
• Gene mutation encodes complementary subcomponents that are vital for the immune function

Symptoms of Ehlers Danlos Syndrome

• Highly elastic & velvety skin
• Muscle fatigue
• Loose joints
• Muscle pain
• Collapsed lung
• Protruding eyes
• Fragile blood vessels
• Sunken cheeks
• Thin Nose
• Transparent skin
• Thin lips
• Chronic pain
• Easy bruising
• Benign growth on elbows & knees
• Chronic degenerative joint disease
• Delicate skin
• Redundant skin folds on the eyes
• Premature osteoarthritis
• Digestive problems like constipation & heartburns
• Problems with bladder control
• Increased heart rate & experience of dizziness while standing up
• Joints dislocate easily
• Problems with internal organs like organ prolapsed & mitral valve prolapse

Diagnosis of Ehlers Danlos Syndrome

• Genetic test
• Skin biopsy
• Echocardiogram
• Blood test for mutation in specific genes
• DNA test to confirm presence of a defective gene in the embryo

Complications of Ehlers Danlos Syndrome

The disorder of the connective tissue has a wide range of implications for the health. Firstly, the joints become excessively flexible leading to easier dislocation of the joints. Due to this, a person may also be subject to severe pain in the joints and muscles. People who suffer from this syndrome are more likely to develop arthritis at a younger age in comparison to others.

Defects in the connective tissue make the healing process slower than usual. The wounds take a longer time to heal which causes scarring. Moreover, people who have EDS take a longer time to recover from any surgery or operation because of the time is taken for the wound to heal.

Prevention of Ehlers Danlos Syndrome

• Use sunscreen to protect the skin
• Avoid contact spots
• To minimize the pressure on the joints, use assistive devices
• Avoid the use of harsh soaps that can make the skin dry and cause allergic reactions
• Avoid lifting heavy weights

Treatment of Ehlers Danlos Syndrome

• Patients can use the services of an occupational therapist who will give valuable advice about the management of daily activities and recommend certain equipment for smooth functioning
• Individuals can learn about the primary causes, the source of inheritance and the risks of transferring the syndrome to their children through genetic counseling
• Seeking help from a physiotherapist may help to manage the pain in the muscle and joints and further strengthen them to avoid injuries
• Absorbic acid or Vitamin C can be given to patients to avoid easy bruising
• Certain medications can be taken to deal with the pain and weakness in the joints and muscles
• In cases where healing through exercise and medication is not possible, doctors may suggest surgeries to repair any damage

When to visit the doctor?

Some of the symptoms of EDS are very common such as joint and muscle pain. If the pain continues for a long time without any specific reason, the individual must consult a general physician. The general physician will examine the person and suggest a rheumatologist (joint specialist) if there is a necessity. Thorough diagnosis will help to clear any doubts about the factors causing such a syndrome and proper treatment will be administered as per the requirement.

Ehlers Danlos Syndrome Pictures:

 

 

Stretchy Skin. Image Source: en.wikipedia.org

 

Hypermobile Joints. Image Source: en.wikipedia.org

 

Image Source: www.pcds.org.uk Image Source: commons.wikimedia.org