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Multiple Epiphyseal Dysplasia (MED)

What is multiple epiphyseal dysplasia?

Multiple epiphyseal dysplasia (MED) is a rare disease that impacts the epiphysis, which is the ends of long bones. There are two forms, defined by how they are inherited: one is passed down in a recessive pattern while the other dominant. 

What are the symptoms of multiple epiphyseal dysplasia?

MED symptoms include:

  • Double-layer kneecaps
  • Misalignment that causes problems in the:
    • Hips
      • Subluxation and Perthes disease can also cause hip issues
    • Knees
    • Ankles
  • Premature arthritis

What causes multiple epiphyseal dysplasia?

Mutations in numerous genes cause the dominant form of MED, such as COMP, COL9A1, COL9A2, COL9A3, and MATN3. The thing that these genes have in common is that they hold the instructions for proteins that exist in the spaces of chondrocytes, or cartilage-forming cells. When these proteins are altered, cartilage and bone formation is also altered. On the other hand, the recessive form of MED is caused by an altered SLC26A2 gene. This mutation changes the structure of cartilage as it develops, which stops the proper bone formation.

How is multiple epiphyseal dysplasia diagnosed?

The first step is to conduct an evaluation of a patient’s medical history. Next steps are a physical exam and X-ray of the areas where pain is present, typically the pelvis, shoulders, and lower extremities. 

What are the treatments for multiple epiphyseal dysplasia?

Treatment should be individualized to each patient based on the presentation of their symptoms. Options are:

  • Total joint replacements
    • Option for the shoulders, knees, and hips
  • Hip realignment surgery
  • Excision of patella
  • Guided growth of the lower extremities 
  • Osteotomies

Where can I find out more about multiple epiphyseal dysplasia?

MED Articles