The primary cause of Arthrogryposis Multiplex Congenita (AMC) is decreased fetal movement in utero, also known as fetal akinesia. While there isn't a single definitive cause, reduced movement during development disrupts normal joint and tissue formation.
Here's a more detailed breakdown:
-
Fetal Akinesia: This is the central factor. Normal fetal movement is crucial for joint development. Lack of movement leads to contractures (fixed joints).
-
Timing Matters: Joint development is typically normal in the early stages of growth. Movement becomes essential later on for proper tissue structure and joint mobility.
-
Multiple Underlying Causes: Fetal akinesia can be caused by a variety of factors, including:
- Neurological Conditions: Problems with the fetal brain, spinal cord, or nerves can impair movement.
- Muscle Disorders: Myopathic causes where the muscles themselves are unable to properly contract.
- Connective Tissue Abnormalities: Issues with collagen or other connective tissues can restrict movement.
- Uterine Problems: Physical constraints within the uterus (e.g., not enough amniotic fluid).
- Genetic Factors: Many cases of AMC have a genetic component.
-
Joint Development: The process of joint development relies on movement. With adequate movement, joints form properly. When this process is disrupted, the joint may develop abnormally.
In summary, while decreased fetal movement in utero is the key characteristic of Arthrogryposis Multiplex Congenita development, the specific reason for the lack of movement can vary and may involve neurological, muscular, connective tissue, uterine, or genetic factors.
