Arthrogryposis causes
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
Causes
The cause as such, is unknown though there have been several suggestions and factors suggested to play a role in AMC. This includes hyperthermia of the fetus, prenatal virus, fetal vascular compromise, septum of the uterus, decreased amniotic fluid, muscle and connective tissue developmental abnormalities. In general, the causes can be classified into extrinsic and intrinsic factors.
Extrinsic
- There is insufficient room in the uterus for normal movement. For example, fetal crowding; the mother may lack a normal amount of amniotic fluid or have an abnormally shaped uterus.
Intrinsic
- Musculoskeletal/Neuromuscular - Muscles do not develop properly (atrophy). In most cases, the specific cause for muscular atrophy cannot be identified. Suspected causes include muscle diseases (for example, congenital muscular dystrophies), maternal fever during pregnancy, and viruses, which may damage cells that transmit nerve impulses to the muscles.
- Neurological - Central nervous system and spinal cord are malformed. In these cases, a wide range of other conditions usually accompanies arthrogryposis.
- Connective Tissue - Tendons, bones, joints or joint linings may develop abnormally. For example, tendons may not be connected to the proper place in a joint.
Research has shown that anything that prevents normal joint movement before birth can result in joint contractures. The joint itself may be normal. However, when a joint is not moved for a period of time, extra connective tissue tends to grow around it, fixing it in position. Lack of joint movement also means that tendons connecting to the joint are not stretched to their normal length; short tendons, in turn, make normal joint movement difficult. (This same kind of problem can develop after birth in joints that are immobilized for long periods of time in casts.)
The principal cause of AMC is believed to be decreased fetal movements (akinesia) caused by maternal or fetal abnormalities. It is associated with neurogenic and myopathic disorders. It is believed that the neuropathic form of AMC involves a deterioration in the anterior horn cell leading to muscle weakness and fibrosis. [1]
In most cases, arthrogryposis is not a genetic condition and does not occur more than once in a family. In about 30% of the cases, a genetic cause can be identified. The risk of recurrence for these cases varies with the type of genetic disorder.There is a rare autosomal recessive form of the disease known to exist.
References
- ↑ Berkow R ed. The Merck Manual of Diagnosis and Therapy. 16th ed. . Rathway, NJ: Merck Research Laboratories;1992:2075