Ehlers-Danlos Syndrome

Key mechanism 1: Collagen synthesis and post-translational modification defects

• In classical EDS (OMIM #130000), mutations in COL5A1 or COL5A2 genes cause defective type V collagen synthesis. Type V collagen functions as an essential nucleator of fibril formation, organizing and regulating the incorporation of more abundant type I collagen. When type V collagen is abnormal or deficient, the entire collagen fibril architecture becomes disorganized, resulting in structurally weak, mechanically compromised fibrils that cannot provide normal tensile strength. Consequently, skin becomes hyperextensible (stretches excessively), scars heal poorly with characteristic "tissue paper" appearance, and joints become hypermobile due to lax ligamentous support.
• Type I collagen mutations directly produce osteogenesis imperfecta features when severe enough to involve EDS-related genes.

Key mechanism 2: Vascular integrity defects and smooth muscle dysfunction

• Vascular EDS (vEDS), caused by COL3A1 mutations affecting type III collagen, represents the most life-threatening subtype. Type III collagen comprises 80-90% of dermal collagen and is the primary structural collagen in blood vessel walls (tunica media and adventitia), hollow organs, and the gastrointestinal tract. Mutations produce either absent or aberrant type III collagen. The consequences are catastrophic: blood vessel walls lose tensile strength and elastic recoil, predisposing to spontaneous arterial rupture at any age; hollow viscera become fragile and prone to perforation; and the characteristic skin hyperextensibility paradoxically reflects thin, translucent skin (not elastic) with visible veins. The pathophysiology explains why vEDS patients require preventive vascular surgery and surveillance because rupture can occur without warning, often fatally.

Key mechanism 3: Lysyl hydroxylase and lysyl oxidase deficiency

• Kyphoscoliotic EDS (kEDS) results from mutations in PLOD1 (lysyl hydroxylase-1) or LOX (lysyl oxidase), enzymes essential for post-translational collagen modification. Lysyl hydroxylase hydroxylates specific lysine residues in procollagen, generating hydroxylysine residues. These residues then serve as the foundation for aldol cross-link formation catalyzed by lysyl oxidase, which oxidatively deaminates lysine and hydroxylysine to generate aldehydes (allysine and hydroxyallysine) that spontaneously condense to form stable cross-links between collagen molecules. Without adequate cross-linking, collagen fibers cannot achieve mechanical strength despite normal synthesis and structure. This produces severe connective tissue fragility, progressive kyphoscoliosis (reflecting vertebral and disc vulnerability), and eye abnormalities (ocular fragility from weak scleral collagen).

Key mechanism 4: Tenascin-X deficiency and protease dysregulation

• Tenascin-X EDS, from TNXB mutations, results in deficiency of this matrix protein that normally regulates protease activity and tissue remodeling. Tenascin-X modulates the activity of matrix metalloproteinases (MMPs) and prevents excessive collagen degradation. Its deficiency paradoxically results in both increased collagen turnover and decreased collagen organization, producing skin hyperextensibility and joint hypermobility.

Key mechanism 5: Dermatosparaxis and procollagen processing defects

• Dermatosparactic EDS (dEDS) results from ADAMTS2 mutations affecting procollagen N-proteinase (a disintegrin and metalloproteinase with thrombospondin motifs), which cleaves the N-terminal propeptide from type I and III procollagen molecules. Without proper processing, procollagen cannot polymerize into organized fibrils. This produces extremely severe skin fragility with blistering and scarring beginning at birth, the most severe skin presentation of any EDS type.

Primary/Genetic Causes (Inherited EDS - All Subtypes)

• Classical EDS (cEDS): Autosomal dominant mutations in COL5A1 (chromosome 9) or COL5A2 (chromosome 1), accounting for ~90% of classical cases. Less commonly, COL1A1 mutations occur. Clinical context: Most common symptomatic EDS after hypermobile type; typically diagnosed in childhood or early adulthood; accounts for the classic presentation of skin hyperextensibility with poor wound healing and atrophic scars.

• Hypermobile EDS (hEDS): Until recently considered a diagnosis of exclusion; now increasingly attributed to molecular defects being discovered in genes affecting collagen-modifying enzymes (FKBP14, TNXB, B4GALT7, B3GALT6, C1R, C1S, PRDM16, CHST14) or proposed to involve autosomal dominant inheritance with incomplete penetrance. Clinical context: Most common form; predominantly affects women (8:1 ratio); presents with generalized joint hypermobility and chronic pain; mimics fibromyalgia and somatization disorder, leading to delayed diagnosis; represents a significant population health problem given its prevalence.

• Vascular EDS (vEDS): Autosomal dominant COL3A1 mutations (chromosome 2) on approximately 80% of all human collagen type III. De novo mutations account for ~25% of cases, meaning a negative family history does not exclude the diagnosis. Clinical context: Highest mortality and morbidity of all EDS types; requires lifelong vascular surveillance; most likely to present with sudden, life-threatening complications; diagnosis mandates preventive medical intervention.

• Kyphoscoliotic EDS (kEDS): Autosomal recessive mutations in PLOD1 (lysyl hydroxylase-1) or LOX (lysyl oxidase). Clinical context: Rare subtype; characterized by severe, progressive skeletal deformity; most consistent subtype phenotype; progressive nature requires aggressive orthopedic management.

• Periodontal EDS (pEDS): Autosomal recessive C1R or C1S mutations (complement cascade genes). Clinical context: Rare; presents with severe, early-onset periodontitis leading to premature tooth loss, often before diagnosis of EDS itself; may involve immune dysregulation.

• Dermatosparactic EDS (dEDS): Autosomal recessive ADAMTS2 mutations. Clinical context: Rarest form; most severe skin fragility phenotype; manifest from birth with severe blistering and scarring; minimal systemic involvement beyond skin.

• Other rare forms: Including arthrochalasia EDS (COL1A1/A2 mutations; autosomal dominant), cardiac-valvular EDS (COL1A2 mutations), myopathic EDS (COL12A1 mutations), and others.

Cardinal Symptom 1: Skin Hyperextensibility

Cardinal Symptom 2: Joint Hypermobility and Chronic Pain

Cardinal Symptom 3: Tissue Fragility and Poor Wound Healing

Physical Exam Finding 1: Characteristic Skin Features

• Velvety texture and hyperextensibility (cEDS, hEDS, some others)
• Thin, translucent skin with visible veins and lack of true elasticity (vEDS—skin stretches but feels inelastic)
• Striae and pseudo-scarring: Spontaneous white lines resembling stretch marks but not from weight gain; red or purple striae in some subtypes
• Molluscoid pseudotumors: Papules and nodules at sites of trauma, particularly elbows and knees, from extravasated collagen
• Spheroids: Small firm papules on forearms and shins from subcutaneous collagen nodules

Physical Exam Finding 2: Skeletal Manifestations

• Progressive kyphoscoliosis: Particularly severe in kyphoscoliotic EDS; often present from childhood and progresses
• Flat feet (pes planus) and hyperpronation from weak ligamentous support
• Chest wall deformities: Pectus carinatum or excavatum from weak costal cartilage
• Micrognathia (small jaw) in some subtypes
• Tall stature with long limbs and arachnodactyly in some patients (mimicking Marfan syndrome)

Clinical Variant 1: Hypermobile EDS (hEDS) - Most Common and Most Challenging

• Generalized joint hypermobility (Beighton ≥6)
• Chronic, widespread musculoskeletal pain often severe and disabling
• Gastrointestinal dysmotility (GERD, IBS-like symptoms, gastroparesis) affecting >50% of patients
• Dysautonomia (orthostatic intolerance, POTS) in substantial proportion
• Minimal or absent skin hyperextensibility (major difference from classical EDS)
• Skin may be soft but not visibly stretchy
• Often misdiagnosed as fibromyalgia, chronic fatigue syndrome, or somatization disorder; diagnosis delayed 5-10 years on average
• Female predominance (8:1) with symptom onset typically in adolescence

Clinical Variant 2: Vascular EDS (vEDS) - Most Life-Threatening

• Thin, translucent skin with visible veins (not truly elastic)
• Characteristic facial features: small chin (micrognathia), large eyes, thin nose, narrow face
• Joint hypermobility typically mild to moderate (unlike other EDS types)
• Spontaneous arterial rupture: carotid, coronary, celiac, mesenteric, or aortic arteries at risk; can occur at any age with minimal trauma or spontaneously
• Visceral fragility: GI perforation, uterine rupture during pregnancy, splenic rupture
• Bruising with minimal trauma often precedes major vascular events
• Easy bleeding and poor wound healing
• Average life expectancy approximately 48-50 years without aggressive preventive intervention
• Structural echocardiographic abnormalities may be absent despite high rupture risk

Clinical Variant 3: Classical EDS (cEDS)

• Marked skin hyperextensibility and velvety texture
• Atrophic scarring and poor wound healing
• Joint hypermobility mild to moderate
• Molluscoid pseudotumors and spheroids characteristic
• Tissue fragility significant but less severe than vascular type
• Relatively good prognosis; most patients reach normal lifespan
• Generally fewer systemic complications than vascular type

Other Presentations

• Periodontal EDS: Severe, early-onset periodontitis causing tooth mobility and loss by adolescence or young adulthood; minimal other systemic EDS features
• Kyphoscoliotic EDS: Progressive severe kyphoscoliosis (often noted by age 5); eye complications (blue sclerae, myopia, rupture); severe tissue fragility; progressive course
• Dermatosparactic EDS: Severe skin blistering and erosions from birth; extreme fragility; redundant skin; minimal systemic features beyond skin

Diagnostic Approach - Clinical Assessment

History-Taking Pearls

• Detailed family history (inheritance pattern; affected relatives; unexplained deaths particularly sudden vascular events)
• Age of symptom onset and progression
• Joint pain severity and functional impact
• History of spontaneous bruising, hematomas, or poor wound healing
• Obstetric complications (premature rupture of membranes, uterine rupture during labor)
• GI symptoms and dysmotility
• Orthopedic history (subluxations, sprains, reconstructions)
• Psychiatric diagnoses—many hEDS patients have prior fibromyalgia or somatization diagnoses
• Screening for life-threatening complications in vascular EDS

Physical Exam Pearls

• Beighton score systematically quantifies joint hypermobility; score ≥6 indicates generalized hypermobility in adults (≥5 in children <16)
• Assess skin character specifically: Is it visibly stretchy (cEDS, hEDS) or thin/translucent with visible veins (

Immediate stabilisation (suspected arterial or visceral rupture)

• Hemodynamic resuscitation with permissive hypotension: transfuse and control blood pressure; friable tissue-paper vessels tear on clamping and sutures cut through, so vascular surgery and interventional radiology favor conservative or covered-stent management over open repair when the patient is stable.
• Avoid catheter arteriography: diagnostic puncture and wire manipulation can dissect the access vessel. Noninvasive CTA/MRA is the imaging of choice.

First-line chronic therapy

• Physical therapy, not surgery, is the foundation: low-resistance, closed-chain strengthening and proprioceptive training stabilize joints that lack ligamentous restraint; bracing, ring splints, and orthotics offload hypermobile joints.
• Analgesia: acetaminophen first; NSAIDs are used cautiously because platelet inhibition compounds baseline capillary fragility. Neuropathic/central pain agents (gabapentinoids; SNRI such as duloxetine) are preferred escalation. Consistent with CDC opioid prescribing guidance, chronic opioids are discouraged — tolerance, hyperalgesia, and worsened gut dysmotility.
• Dysautonomia/POTS: volume expansion with salt and fluid, compression garments, and graded recumbent exercise before drugs; fludrocortisone, midodrine, or a low-dose beta blocker per AHA/HRS expert consensus on POTS.

Subtype-specific escalation

• Vascular EDS: blood-pressure lowering to reduce arterial wall stress. Celiprolol, a beta-1 blocker with partial beta-2 agonism, reduced arterial events in the French BBEST trial and is endorsed for vEDS, but it is not marketed in the US, so another beta blocker or an ARB is substituted. Serial noninvasive arterial imaging and a medical-alert bracelet are standard.
• Kyphoscoliotic EDS: bracing and orthopedic spinal stabilization; ascorbic acid is often supplemented because vitamin C is the cofactor for the deficient lysyl hydroxylase, though benefit is unproven.

Contraindicated/avoid

• Contact sports, heavy isometric lifting, and Valsalva straining; elective colonoscopy and arteriography in vEDS; anticoagulants/antiplatelets unless compelling; elective cosmetic surgery. Surgical joint stabilization frequently fails as sutures pull through lax tissue.

Emergencies — vascular EDS (COL3A1)

• Spontaneous arterial rupture or dissection: absent/abnormal type III collagen leaves the media and adventitia without tensile strength. Signaled by abrupt chest, flank, or abdominal pain with hypotension in a young patient without atherosclerotic risk factors; mid-sized arteries (splenic, renal, iliac, mesenteric) are typical. Leading cause of death.
• Spontaneous hollow-viscus perforation: the sigmoid colon is the classic site — sudden peritonitis without diverticulitis or instrumentation.
• Carotid-cavernous sinus fistula: rupture of the intracavernous carotid produces pulsatile exophthalmos, chemosis, and an orbital bruit; a vEDS-defining event requiring urgent neurointervention.
• Uterine rupture and peripartum arterial rupture/hemorrhage: pregnancy in vEDS is high-risk; ACOG-guided delivery at a tertiary center with multidisciplinary planning is standard.
• Spontaneous pneumothorax/hemothorax: fragile pleura and pulmonary vessels; sudden dyspnea and pleuritic pain.

Non-emergent disease complications

• Recurrent subluxation/dislocation and premature osteoarthritis: chronic joint instability drives abnormal load distribution and cartilage wear.
• Chronic widespread pain, fatigue, and deconditioning, frequently with anxiety/depression — a major disability driver in hypermobile EDS.
• GI dysmotility and mast cell activation symptoms: reflux, gastroparesis, constipation, flushing.
• Wound dehiscence, atrophic scarring, hernias, and rectal/pelvic organ prolapse from failed tissue apposition.
• Restrictive lung disease from progressive kyphoscoliosis; globe rupture and retinal detachment in kyphoscoliotic EDS; early tooth loss in periodontal EDS.
• Cervical spine and craniocervical instability: occipital headache, myelopathic signs — flag before airway manipulation.

Treatment-related complications

• NSAID-associated bruising and GI bleeding; opioid dependence and hyperalgesia.
• Perioperative/anesthetic risk: reported resistance to local anesthetics, fragile skin injury from tape and positioning, and cervical injury during intubation.
• Fludrocortisone: hypokalemia and hypertension; midodrine: supine hypertension.

• COL3A1 = type III collagen = vascular EDS: the only subtype that kills young. Buzzwords are thin, translucent skin with visible veins, easy bruising, and an acrogeric face (thin nose, small chin, prominent eyes). A quarter of cases are de novo, so a negative family history does not exclude it.
• Single best next step in suspected vEDS with vascular symptoms: noninvasive imaging (CTA or MRA) plus genetic confirmation — never catheter arteriography, which can dissect the punctured vessel. Confirmatory testing is COL3A1 sequencing.
• The association examiners test: spontaneous sigmoid colon perforation or a carotid-cavernous fistula (pulsatile exophthalmos with orbital bruit) in a young adult with hyperextensible skin — both are vEDS until proven otherwise.
• Classical EDS = COL5A1/COL5A2 (type V collagen), which nucleates type I fibrils. Buzzwords: molluscoid pseudotumors, atrophic "cigarette-paper" scars, velvety hyperextensible skin.
• Kyphoscoliotic EDS = PLOD1 (lysyl hydroxylase); vitamin C is the enzyme cofactor, and ocular fragility with blue sclerae plus congenital hypotonia is the stem. Contrast with Menkes disease, where copper deficiency disables lysyl oxidase.
• Common distractor — Marfan syndrome: FBN1/fibrillin-1, upward lens subluxation, aortic root dilation. EDS does not cause ectopia lentis. Homocystinuria gives downward lens subluxation with thrombosis; osteogenesis imperfecta (COL1A1/A2) gives fractures, blue sclerae, and conductive hearing loss; Loeys-Dietz adds bifid uvula, hypertelorism, and arterial tortuosity.
• Do not swap the collagen types: type V → classical, type III → vascular, type I → osteogenesis imperfecta/arthrochalasia.
• Management pearls: physical therapy and joint protection are first-line for hypermobility; surgical stabilization commonly fails because sutures cut through lax tissue. Contact sports, isometric straining, and elective colonoscopy are avoided in vEDS.