I. Pathophysiology & Clinical Spectrum

Ehlers-Danlos syndrome (EDS) is a heterogeneous group of inherited connective tissue disorders caused by defects in collagen synthesis, processing, or structure—most commonly COL1A1, COL1A2, COL3A1, COL5A1, COL6A1–3, and genes involved in collagen modification (FKBP14, SERPINF1), extracellular matrix organization (ADAMTS2, ZNF469), or vascular integrity (ACTA2, TGFB2/3). The 2017 classification recognizes 13 subtypes, but three account for the vast majority of clinically significant cases:

Note: hEDS remains a clinical diagnosis—no validated biomarkers or genetic test exists as of 2024 (Pericat et al., Am J Med Genet C, 2023).

II. Diagnostic Evaluation: A Stepwise Approach

A. Clinical Suspicion Triggers (Red Flags)

Refer for EDS evaluation when ≥1 of the following is present:

• Abnormal bleeding/bruising: Spontaneous bruising >5 cm, post-procedural hemorrhage disproportionate to trauma, menorrhagia (especially in cEDS/vEDS).
• Tissue fragility signs: Atrophic “cigarette-paper” scars, molluscoid pseudotumors (fat pads over pressure points), subcutaneous spheroids.
• Symptomatic joint hypermobility:
  • Beighton score ≥6/9 in adults (<50% sensitivity in older adults)
  • Plus ≥2 of: recurrent dislocations (≥1 full-term pregnancy ± prior delivery), chronic pain (≥3 months),早 osteoarthritis <40 y
• Systemic features: Gastrointestinal dysmotility (IBS-like symptoms), autonomic dysfunction (POTS: HR↑ >30 bpm on stand, orthostatic hypotension), craniocervical instability (CCI), pelvic organ prolapse.
• Vascular events: Spontaneous carotid-cavernous sinus fistula, spontaneous renal/splenic artery rupture, class III pregnancy complications (uterine rupture, cervical insufficiency).
• Developmental delays: Hypotonia in infancy → delayed walking + persistent joint hypermobility.

B. Diagnostic Workup

1. Clinical assessment:
   • Beighton score + 5-PHQ (for hEDS screening): 5-item questionnaire assessing joint pain, dislocations, hernias, mitral valve prolapse, and flat feet.
   • Skin assessment: Elasticity test (lateral neck stretch >2–3 cm), texture (soft/doughy = cEDS; velvety = hEDS).
   • Vascular screening: Raise hand test (positive if hand remains pale >5 sec after elevation), capillary refill >3 sec.
2. Genetic testing (per ACMG 2021 guidelines):
   • Suspected cEDS/vEDS: Targeted COL5A1/COL5A2 and COL3A1 sequencing + deletion/duplication analysis (Sanger or multi-gene panel).
   • Suspected hEDS: No gene test available. Diagnosis requires strict criteria (2017 International Criteria):
     • Major: Beighton ≥5/9 and ≥2 systemic features (e.g., Marfanoid habitus, ocular signs, skin changes)
     • Major + minor criteria (e.g., positive 5-PHQ, family history, mitral valve prolapse)
   • Vascular imaging (for vEDS pre-symptomatically):
     • Baseline MRA/CTA of head/neck and abdomen/pelvis if COL3A1+, even if asymptomatic (Hoeppner et al., JAMA Netw Open, 2022).
     • Avoid angiography due to dissection risk.
3. Biochemical testing (limited role):
   • Collagen electrophoresis of dermal fibroblasts: Abnormal α-chains in cEDS (delayed migration), reduced type III collagen in vEDS.
   • Not recommended for hEDS diagnosis due to low sensitivity/specificity.

C. Differential Diagnosis (Key Entities)

III. Management: Multimodal, Individualized, and Risk-Stratified

A. hEDS & cEDS

1. First-line: Conservative musculoskeletal optimization
   • Exercise therapy (strongest evidence):
     • Proprioception + neuromuscular training: 3x/week for ≥12 weeks reduces pain/dislocations by 40–60% (Mientjes et al., Rheumatology, 2021).
     • Focus on deep stabilizers: transversus abdominis, multifidus, hip abductors.
     • Avoid high-impact activities (running, contact sports).
   • Bracing: Ankle/knee braces during activity; lumbar orthosis for CCI suspicion.
2. Pharmacotherapy:
   • Pain: Acetaminophen → low-dose gabapentin/ pregabalin (first-line neuropathic). Avoid opioids long-term.
   • Dysautonomia: Fludrocortisone, midodrine; exercise-based rehab for POTS.
   • GI motility: Prucalopride, erythromycin; avoid anticholinergics.
3. Comorbidity management:
   • Screen for psychiatric comorbidities: 50–75% have anxiety/depression (EDS-specific stressors + neurobiological vulnerability).
   • Pelvic floor PT for prolapse/dyspareunia.
   • Dental occlusion assessment (temporomandibular joint instability).

B. vEDS: High-Risk, Protocol-Driven Care

1. Avoid invasive procedures:
   • Absolute contraindications: Arterial catheterization, lumbar puncture, colonoscopy (perforation risk ↑ 30%).
   • Relative contraindications: Biopsies (especially skin), elective surgery.
2. Acute vascular events:
   • Arterial dissection/rupture: Immediate BP control (SBP <120 mmHg), beta-blockers (metoprolol 25–50 mg BID), avoid ACEi if renal artery involvement.
   • Surgery: Reserved for life-threatening events; outcomes poor (mortality 35% in emergency repair vs. 10% general population). Endovascular stents high failure rate due to vessel fragility.
3. Prophylaxis:
   • Collagen stabilizers: Oral vitamin C (4 g/day) showed reduced arterial events in COL3A1 mouse models (not yet human-trial confirmed).
   • Pregnancy management: Serial uterine wall thickness monitoring; delivery at ≥37 wks via C-section (uterine rupture risk 12–25%).

C. When Surgery Is Indicated

• General principle: Delay non-urgent procedures until collagen maturity peaks (~age 25).
• Perioperative considerations:
  • Anesthesia: Difficult intubation (atlantoaxial instability), poor IV access, tissue friability.
  • Suturing: Use deep interrupted sutures; avoid staples (poor tissue grip).
  • Post-op: Strict BP control, prolonged monitoring for dehiscence.

IV. Emerging Evidence & Future Directions

• hEDS biomarkers: Circulating miR-21-5p and LOX levels under investigation (Pepin et al., Genet Med, 2023).
• TGF-β modulators: Losartan trials ongoing for vEDS-related vascular dilation.
• Gene therapy: CRISPR-based correction in fibroblasts (preclinical for cEDS).

V. Key Clinical Takeaways

1. hEDS is a diagnosis of exclusion—rule out Marfan, LDS, HSD first.
2. Screen vEDS aggressively: 50% of patients die by age 50 from vascular events (Guillot et al., Circulation, 2022).
3. Physical therapy is disease-modifying—not symptomatic relief alone.
4. Multidisciplinary care reduces disability: Rheumatology + PT + cardiology/vascular surgery for vEDS, genetics for counseling.

Referral Indications: Suspected cEDS/vEDS → clinical genetics; hEDS + functional impairment → EDS specialty clinic (per 2023 International Consensus Statement).

Sources: Malfait et al. (2017) Am J Med Genet C; Pyeritz (2022) Circulation; Francomano et al. (2023) Genet Med; EDS Society Clinical Guidelines v3.1 (2024).