Ehlers-Danlos Syndrome: Key Points from MedlinePlus Genetics

Overview

• Ehlers-Danlos syndrome (EDS): A group of disorders affecting connective tissues, which support various parts of the body including skin, bones, and blood vessels.
• Symptoms range from mildly loose joints to severe, life-threatening complications.

Classification

• Original Classification: 11 types identified by Roman numerals.
• Villefranche nomenclature (1997): Simplified to six types with descriptive names.
• Updated Classification (2017): Includes 13 types, accounting for rare forms.

Common Symptoms

• Joint Hypermobility: Common in most forms; hallmark of hypermobile type.
  • Infants/Children: May have weak muscle tone, delayed motor skills development.
• Skin Features:
  • Soft, velvety, highly elastic, and fragile skin.
  • Tendency to bruise easily with abnormal scarring in some forms.
• Vascular Symptoms:
  • Bleeding issues due to ruptures in blood vessels and organs.
  • Potential for stroke and complications during pregnancy.

Specific Types and Unique Features

• Classical Type: Cigarette paper scars.
• Dermatosparaxis Type: Loose, sagging skin.
• Vascular Type: Easy bruising, internal bleeding, risk of uterine rupture.
• Cardiac-Valvular Type: Severe heart valve problems.
• Kyphoscoliotic Type: Severe spinal curvature affecting breathing.
• Brittle Cornea Syndrome: Thin cornea and other eye issues.

Prevalence

• Combined prevalence: At least 1 in 5,000 worldwide.
• Hypermobile Type: 1 in 5,000 to 20,000.
• Classical Type: 1 in 20,000 to 40,000.

Genetic Causes

• Mutations: At least 20 genes involved.
• Common Genes: COL5A1, COL5A2, COL1A1, COL1A2, COL3A1, TNXB, ADAMTS2, PLOD1, FKBP14.
• Collagen Role: Provides structure and strength to connective tissues; mutations lead to EDS features.
• Non-collagen Genes: Some associated genes don't directly affect collagen.

Inheritance Patterns

• Autosomal Dominant: Classical, vascular, arthrochalasia, periodontal forms.
  • One altered gene copy sufficient for disorder.
• Autosomal Recessive: Classical-like, cardiac-valvular, dermatosparaxis, kyphoscoliotic, spondylodysplastic, musculocontractural types, brittle cornea syndrome.
  • Two altered gene copies needed.
• Myopathic Type: Can be either dominant or recessive.

References and Resources

• OMIM Catalog: Various types of EDS listed with specific identifiers.
• Scientific Articles: PubMed references for further reading and research.

These notes provide a concise overview of Ehlers-Danlos Syndrome as described in the MedlinePlus Genetics resource, detailing its classification, symptoms, genetic causes, and inheritance patterns.