Myophatic EDS (mEDS)

ESTIMATED PREVALENCE: <1 in 1,000,000 [60]

INHERITANCE PATTERN: Autosomal Recessive AND Autosomal Dominant (both found)

SYMPTOMS [61, 62]:

Myopathic EDS (mEDS) is usually characterized by myopathy (weakness) of the muscles and/or muscle hypotonia (poor muscle tone), that begins in childhood. There is often delayed motor development, as a result. Yet, in young adulthood, someone with mEDS often experiences a grace period, where these muscles become stronger until the patient’s forties, when they may become weak again. Often, patients with mEDS have large joint contractures (knees, hips, elbows, etc.), or shortening of the large joints/limbs due to tight muscles.

As with most forms of EDS, mEDS often presents with hypermobility (usually of the extremities), thick raised scarring, soft, doughy skin, and/or loose skin.

DIAGNOSTIC CRITERIA [63]:

To diagnose mEDS, the following formula must be satisfied, at the minimum:

Major Criterion #1 + one (1) other Major Criterion OR three (3) Minor Criteria

To diagnose mEDS, a patient must satisfy Major Criterion #1 (congenital muscle hypotonia, and/or muscle atrophy, which improves with age), plus one other Major Criterion or three (3) Minor Criteria. When diagnostic criteria are met, molecular testing is required to confirm a positive diagnosis.

Major Diagnostic Criteria

• Congenital muscle hypotonia, and/or muscle atrophy, which improves with age
• Proximal joint contractures (knee, hip, and elbow)
• Hypermobility of distal joints

Minor Diagnostic Criteria

• Soft, doughy skin
• Atrophic scarring
• Motor developmental delay
• Myopathy on muscle biopsy

Genetic Markers:

COL12A1