What is Arthrogryposis?

 

Arthrogryposis Multiplex Congenita (AMC), or simply arthrogryposis, is an umbrella diagnosis describing joint contractures in two or more areas of the body (e.g. upper limbs, lower limbs, spine, jaw, etc.) present at birth. There are over 400 specific conditions which have been recognized to have AMC. Over 330 different genes have been recognized to have mutations associated with AMC. These genes can be sorted into 22 tissue specific pathways, which promise possible therapies in the future.

Each specific type of AMC is relatively rare. One in about 3000 births (including live births and stillbirths) have multiple congenital contractures.

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Clinically (in hopes of making a specific diagnosis), the most useful approach is to distinguish three separate types of AMC:

  1. Amyoplasia, an non-hereditary condition, is the most common type of AMC where the fetus fails to grow muscle tissue in the limbs.  Individuals with Amyoplasia have normal intelligence and respond well to therapy.  Occurrence is about 1/10,000.

  2. Affected individuals with intellectual disability often have a gene and/or chromosomal variation.

  3. A large variety of syndromes, often with other system involvement, can include Distal AMC and Pterygium syndromes. These can result in genetic variants, boney abnormalities, connective tissue anomalies, limitation of in utero space (related to uterine anomalies, multiple births, etc.) and maternal illness.

All of these conditions have the common feature of decreased fetal movement in utero, which leads to the arthritic-like stiffness and contractures.

Therapy for the contractures after birth is best provided by a multidisciplinary team in childhood, and involves physical therapy to mobilize contractures shortly after birth, with orthopaedic procedures as appropriate. The goal of therapy is to mobilize joints and align them to maximize abilities.

Little is known about long-term outcomes and which therapies are most appropriate for which specific disorders. 

Do you have AMC?  Learn more about our research and how your experiences are valuable to our community learning more about aging and long-term outcomes.