Histology · Year 1 · from Histology
Case 1: Ehlers-Danlos Syndrome (Classical Type)
Clinical Image
Source: Wikipedia - Ehlers-Danlos Syndrome - CC BY-SA 3.0
Case Presentation
A 19-year-old female college athlete presents to the orthopedic clinic after her third shoulder dislocation in two years. Physical examination reveals remarkable findings: her skin can be stretched far beyond normal limits from the volar forearm and snaps back when released. She demonstrates the ability to touch her thumb to her forearm and hyperextend her elbows beyond 10 degrees. Her skin appears soft and velvety, with multiple atrophic scars over her knees and shins from minor childhood injuries that healed poorly. Family history reveals her mother has similar joint hypermobility. Genetic testing confirms a mutation in the COL5A1 gene encoding type V collagen. She is diagnosed with classical Ehlers-Danlos syndrome and counseled on joint protection strategies, physical therapy to strengthen periarticular muscles, and avoidance of contact sports.
Key Learning Points
- Classical EDS results from mutations affecting type V collagen synthesis, which regulates type I collagen fibril assembly
- Defective collagen produces skin hyperextensibility (stretches >1.5 cm at the volar forearm) and joint hypermobility
- Histologically, collagen fibers appear thin, disorganized, and loosely arranged rather than in normal dense bundles
- The "tissue fragility" leads to poor wound healing, atrophic scarring, and easy bruising