Arthrogryposis multiplex congenita (AMC) is a group of disorders characterized by congenital limb contractures. It manifests as limitation of movement of multiple . Amyoplasia is a condition characterized by a generalized lack in the newborn of muscular It is the most common form of arthrogryposis multiplex congenita ( AMC), where multiple joint contractures are present at birth. Arthrogryposis is. “Amyoplasia Congenita.” Syndromes: Rapid Recognition and Perioperative Implications Bissonnette B, Luginbuehl I, Marciniak B, Dalens BJ. Bissonnette B.
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Arthrogryposis is a general or descriptive term for the development of nonprogressive contractures affecting one or amyoplsia areas of the body prior to birth congenitally. A contracture is a condition in which a joint becomes permanently fixed in a bent flexed or straightened extended position, completely or partially restricting the movement of the affected joint. When congenital contractures occur only in one body area, it is not referred to as arthrogryposis but rather an isolated congenital contracture.
The most common form of an isolated congenital contracture is clubfoot.
AMC: amyoplasia and distal arthrogryposis
When arthrogryposis affects two or more different areas of the body, it may be referred to as arthrogryposis multiplex congenita AMC. The most common form of AMC is Amyoplasia. Arthrogryposis and arthrogryposis multiplex congenita are sometimes used interchangeably. The symptoms of AMC are present at birth congenital.
However, specific symptoms and physical findings can differ greatly in range and severity from one person to another. In most cases, affected infants have contractures of various joints. The joints of the legs and arms are usually affected, the legs are affected more often than the arms.
In addition, the jaws and back may also be affected in individuals with AMC. In most cases, AMC occurs randomly, for no apparent reason sporadic. More than different conditions can cause isolated or multiple contractures and the causes, genetics, specific symptoms, and severity of these disorders vary dramatically. Over genes have been identified as responsible for different types of arthrogryposis. The most common universal symptom of AMC is limited or absent movement around small and large joints contractures.
The contractures are present at birth congenital. The muscles of the affected limbs may be underdeveloped hypoplasticresulting in a tube-shaped limb with a soft, doughy feeling. Soft tissue webbing may develop over the affected joints.
In addition to joint abnormalities, other findings occur with greater frequency in individuals with AMC. These include abnormally slender and fragile long bones of the arms and legs and cleft palate, a condition in which the roof of the mouth fails to fuse together leaving a groove across the top of the mouth.
In males, the testes may fail to descend into the scrotum cryptorchidism. Intelligence may or may not be affected. Approximately one-third of individuals with AMC may have structural or functional abnormalities of the central nervous system. Additional symptoms associated with AMC are related to the underlying disorder that causes the condition in each individual.
The specific symptoms and their severity can vary dramatically based upon the underlying cause.
Amyoplasia is the most common form of AMC. Amyoplasia is a disorder characterized by multiple dongenita of the joints. The shoulders may be internally rotated and drawn inward adductedthe elbows are usually extended, and the wrists are usually flexed.
In most affected individuals, the fingers are flexed and stiff. Although in most cobgenita, the distal joints i. Affected individuals usually have severe clubfoot. Some affected individuals may have dislocated hips. Individuals with Amyoplasia usually have normal intelligence, no significant craniofacial abnormalities, and no other serious abnormalities of internal organs visceral abnormalities.
Amyoplasia – Wikipedia
Amyoplasia is common in one of monozygotic twins. Amyoplasia appears to be sporadic and not recur in families. This subgroup is characterized by multiple congenital contractures. Common symptoms include contractures of two or more areas of the body, less involvement of the proximal joints those joints closest to the center of the bodyand highly variable expressivity, which means that specific symptoms vary greatly even among individuals with the same disorder and even in the same family.
At least 10 different congenitaa of distal arthrogryposis have been identified including Freeman-Sheldon syndrome, Gordon syndrome, trismus-pseudocamptodactyly syndrome, multiple pterygium syndrome and Sheldon-Hall syndrome. For more information on these disorders, choose the specific disorder name as your search term in the Rare Disease Database. The cause of AMC depends on the specific type. For many types, the cause is not fully understood. Arthrogryposis or Congenits is not a specific diagnosis, but a physical finding that can be associated with numerous disorders and conditions.
AMC is thought to be related to decreased movement in utero, which can have multiple causes. Neurologic and muscle problems may well be the most common causes of decreased fetal movement, but connective tissue disorders, maternal illness, and limited space are also common causes.
Some cases of AMC occur as part of rare genetic disorders that are inherited. Some cases of AMC are related to multiple factors including genetic and environmental ones multifactorial inheritance. AMC may occur as part of certain single-gene disorders that can be inherited as autosomal recessive, autosomal dominant or X-linked traits.
AMC may also occur as part of chromosomal disorders e. AMC can also occur as part of certain connective tissue disorders. In addition, some cases of AMC may occur due to abnormalities or disorders associated with improper developmental congenitq the central nervous system or the peripheral nervous system or as part of intrinsic muscle disorders. These disorders may be genetic or may occur due to environmental factors.
The primary underlying mechanism that causes congenital contractures is believed to be decreased fetal movement during development. The joints begin to develop in a fetus around five or six weeks into pregnancy. Motion is essential for the proper development of fetal joints. Congenitw theory, any factor that diminishes or restricts fetal movement can cause congenital contractures. Such factors would include fetal crowding in which there is not enough room for the fetus to move around such as when there are multiple births or uterine structural abnormalities.
Restricted fetal movement can also occur secondary to maternal disorders including viral infections, drug use, trauma or other maternal illness. Low levels of amniotic fluid around the fetus oligohydramnios have also been linked to decreased fetal movement.
Amyoplasia, the most common form of AMC, occurs randomly sporadically. The distal arthrogryposes, another common form of AMC, are usually inherited as autosomal dominant traits. Genetic diseases are determined by the combination of genes for a particular trait that are on the chromosomes received from the father and the mother.
Dominant genetic disorders occur when only a single copy of an abnormal gene is necessary for the appearance of the disease. The abnormal gene can be inherited from either parent, or can be the result of a new mutation gene change only in the affected individual. The risk of passing the abnormal gene from affected parent to offspring is 50 percent for each pregnancy regardless of the sex of the resulting child.
Central and peripheral nervous system disorders that are associated with AMC include a condition in which the brain and spinal cord do not close before birth meningomyelocelethe spinal muscular atrophies, and disorders in which there is incomplete development of certain portions of the brain e. Most of these disorders develop due to multiple factors including genetic and environmental ones multifactorial inheritance.
Less often, AMC may be associated with certain muscle disorders including the muscular dystrophies, certain mitochondrial disorders and a variety of genetic muscle disorders that are present at birth congenital congeinta.
Such disorders are usually inherited. Abnormalities affecting the development of connective tissue can cause AMC as well. Connective tissue is the material between the cells of the body that gives tissues amyop,asia and strength. The abnormal development of connective tissue in the joints can qmyoplasia fetal movements, potentially causing multiple contractures. A lack of joint development or the abnormal fusion of bones synostosis that are normally separate have also been associated with multiple congenital contractures.
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Several disorders, which are associated with abnormalities of connective cognenita development, have been associated with multiple congenital contractures including diastrophic dysplasia, metatropic dwarfism, popliteal pterygium syndrome and Larsen syndrome.
The number of males and females affected by AMC is approximately equal.
The condition has been reported in individuals of Asian, African and European descent. Isolated congenital contractures affect approximately 1 in individuals in the general population. AMC affects approximately 1 in 3, individuals.
AMC is present at birth congenital. A diagnosis of AMC is made based upon identification of characteristic symptoms e. Certain tests may be necessary to determine the underlying cause of AMC including nerve conduction, electromyography and muscle biopsy, which can help diagnose neuropathic or myopathic disorders.
A nerve conduction study measures how rapidly nerves carry an electrical impulse. An electromyography is a test that records electrical activity in skeletal voluntary muscles at rest and during muscle contraction. A biopsy is a procedure in which a small amount of affected tissue e. Imaging studies of the central nervous system CNS and comparative genomic hybridization CGH array, microarray, and exome studies are also useful studies in making diagnoses. The treatment of AMC is directed toward the specific findings that are apparent in each individual.
Standard physical therapy, which can improve joint motion and avoid muscle atrophy in the newborn period is beneficial. Gentle joint manipulation and stretching exercises may also be beneficial. Removable splints for the knees and feet that permit regular muscle movement and exercise are also recommended.
In some cases, surgery may be necessary to achieve better positioning and increase the range of motion in certain joints, especially the ankles, knees, hips, elbows, or wrists. In rare cases, tendon transfers have been performed to improve muscle function.
Tendons are the tissue by which muscle is attached to bone. Genetic counseling may be of benefit for affected individuals and their families. Other treatment is symptomatic and supportive. Information on current clinical trials is posted on the Internet at www. All studies receiving U. Government funding, and some supported by private industry, are posted on this government web site. Arthrogryposes Multiple Congenital Contractures. Management of Genetic Syndromes, 3rd Ed.