Arthrogryposis multiplex congenita
- Amyoplasia congenita
- Arthromyodysplasia congenita
- Congenital amyoplasia
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The exact cause of arthrogryposis multiplex congenita (AMC) is not fully understood. AMC is thought to be related to decreased fetal movement during development, which can occur for a variety of reasons. When a joint is not moved for a period of time, extra connective tissue may grow around it, fixing it in place. Lack of joint movement also means that tendons connected to the joint are not stretched to their normal length, which can make normal joint movement difficult.
In general, there are four causes for decreased fetal movement before birth:
- Abnormal development of muscles. In most cases, the specific cause for this cannot be identified. Suspected causes include muscle diseases, maternal fever during pregnancy, and viruses which may damage the cells that transmit nerve impulses to the muscles.
- Insufficient room in the uterus for normal movement. For example, multiple fetuses may be present, the mother may lack normal amounts of amniotic fluid or there may be uterine structural abnormalities.
- Malformations of the central nervous system (the brain and/or spinal cord). In these cases, arthrogryposis is usually accompanied by a wide range of other symptoms.
- Tendons, bones, joints or joint linings may develop abnormally. For example, tendons may not be connected to the proper place in a joint.
AMC can be a component of numerous condition caused by environmental factors, single gene changes (autosomal dominant, autosomal recessive, X-linked), chromosomal abnormalities and various syndromes.
- Harold Chen, MD, MS, FAAP, FACMG. Arthrogryposis. Medscape Reference. February 2013; http://emedicine.medscape.com/article/941917-overview.
- Arthrogryposis Multiplex Congenita. NORD. February 2013; http://www.rarediseases.org/rare-disease-information/rare-diseases/byID/211/viewAbstract.
- Arthrogryposis: What it is and how it is treated. A National Support Group for Arthrogryposis Multiplex Congenita (AVENUES). http://www.avenuesforamc.com/publications/pamphlet.htm. Accessed 10/15/2013.