arthrogryposis

Arthrogryposis, also known as Arthrogryposis Multiplex Congenita, is a rare congenital disorder that is characterized by multiple joint contractures and can include muscle weakness and fibrosis. It is a non-progressive disease. The disease derives its name from Greek, literally meaning 'curved or hooked joints'. ^{[1] [2] [3] [4] [5] [6] [7] [8] [7] [9] [10]}

There are many known subgroups of AMC, with differing signs, symptoms, causes etc.^[3] In some cases, few joints may be affected and may have a nearly full range of motion. In the most common type of arthrogryposis, hands, wrists, elbows, shoulders, hips, feet and knees are affected. In the most severe types, nearly every joint is involved, including the jaw and back.

Frequently, the contractures are accompanied by muscle weakness, which further limits movement. AMC is typically symmetrical and involves all four extremities with some variation seen.^[5][1]

Classification

Some of the different types of AMC include:

• Arthrogryposis multiplex due to muscular dystrophy.^[11][12]
• Arthrogryposis ectodermal dysplasia other anomalies, also known as Cote Adamopoulos Pantelakis syndrome, Trichooculodermovertebral syndrome, TODV syndrome and Alves syndrome.^[13][14]
• Arthrogryposis epileptic seizures migrational brain disorder.^[15]
• Arthrogryposis IUGR thoracic dystrophy,also known as Van Bervliet syndrome.^[16][17]
• Arthrogryposis like disorder, also known as Kuskokwim disease.^[18]
• Arthrogryposis-like hand anomaly and sensorineural deafness.^[19][20]
• Arthrogryposis multiplex congenita CNS calcification.^[21]
• Arthrogryposis multiplex congenita distal (AMCD)^[22], with a large number of synonyms such as Arthrogryposis multiplex congenita, distal, x-linked (AMCX1)^[23][24] and Arthrogryposis spinal muscular atrophy^[25][26][27]
• Gordon Syndrome, also known as Distal Arthrogryposis, Type 2A.^[28]
• Arthrogryposis multiplex congenita, distal type 2B, also known as Freeman-Sheldon syndrome variant.^[29]
• Arthrogryposis multiplex congenita neurogenic type (AMCN).^[30] This particular type of AMC has been linked to the AMCN gene on locus 5q35.^[31][32]Arthrogryposis multiplex congenita pulmonary hypoplasia, also with a large number of synonyms.^[33][34]
• Arthrogryposis multiplex congenita whistling face, also known as Illum syndrome.^{[35][36][37][38]}
• Arthrogryposis multiplex congenita, distal type 1 (AMCD1).^[39]
• Arthrogryposis ophthalmoplegia retinopathy, also known as Oculomelic amyoplasia.^[40][41][42]
• Arthrogryposis renal dysfunction cholestasis syndrome, also known as ARC Syndrome.^[43][44]

Signs and symptoms

There are numerous symptoms for this group of conditions.^[4] Some of the more common signs and symptoms are associated with the shoulder (internal rotation), elbow (extension and pronation), wrist (volar and ulnar), hand (fingers in fixed flexion and thumb-in-palm), hip (flexed, abducted and externally rotated, often dislocated), knee (flexion) and foot (clubfoot).^[8] Complications may include scoliosis, lung hypoplasia, respiratory problems, growth retardation, midfacial hemangioma, facial and jaw variations, and abdominal hernias. Cognition and language are usually normal.^[5]

Causes

The cause is unknown^[7], although several mechanisms have been suggested. This includes hyperthermia of the fetus, prenatal virus, fetal vascular compromise, septum of the uterus, decreased amniotic fluid, muscle and connective tissue developmental abnormalities. ^[5][6] 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.^[3][9]

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. ^[6]
• 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.^[3][9]

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. ^[45]

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.^[4]There is a rare autosomal recessive form of the disease known to exist ^[7]

Diagnosis

To date, no prenatal diagnostic tools are available to test for the condition. Diagnosis is only used to rule out other causes. This is done by undertaking muscle biopsies, blood tests and general clinical findings rule out other disorders and provides evidence for AMC.^[5]

Treatment

While there is no reversal of this condition, individual quality of life can be greatly improved. As each person will respond differently, and will have different needs, a combination of therapies is beneficial. Physical therapy including stretching (may include casting, splinting of affected joints), strengthening, and mobility training are often provided to improve flexion and range of motion to increase mobility. Occupational therapy can include training in ADL and fine motor skills as well as addressing psychosocial and emotional implications of living with a disability. Since there is a variety of mobility impairments, individually tailored orthopaedic correction is often beneficial. Orthopedic surgery may be elected to correct severely affected joints and limbs and symptoms such as clubfoot, hernia repair and correction of unilateral hip dislocation, in cases where these surgeries improve quality of life.

Prognosis

Individuals with AMC are aided by vigorous therapy and in some cases surgical intervention. This varies to some degree, depending on the severity of mobility reduction.^[5] AMC is not a progressive disorder. Typically these individuals have normal cognition and speech and therefore the potential for productive, rewarding, and independent lives.

Epidemiology

AMC is relatively rare occurring in 1 out of every 3,000 live births.^[5][8] Amyoplasia, characterized by fatty and fibrous tissue replacement of the limb muscles, is the most common form, at 43% of reported cases.^[46] The majority of individuals thrive, with a minority strongly affected by respiratory muscle involvement.

Affected people

• Celestine Tate Harrington, a quadriplegic street musician who performed at the Atlantic City Boardwalk and author of the 1996 book, "Some Crawl and Never Walk."
• Asta Philpot, an American-born man living in England, who was the protagonist of a BBC documentary about prostitution as a mean of offering the chance of sexual experiences to people with disabilities.
• Lee Pearson, a 9-time gold medal winner at the Paralympic games in dressage.
• Sunny Taylor, an American painter and activist.
• Josh Twelves, a YouTube comedian actor from Utah.
• Charles R. Martin Jr., M.D., an American man living in Phoenix who was born with arthrogryposis but through perseverance and drive became the only Medical Doctor in history of the American Medical Association who cared for and performed minor surgical procedures on patients.
• John Nellie Nelson, A Pacific Lutheran University football coach and ambassador to the PLU community.
• Luca "LazyLegz" Petuelli, A Canadian B-boy who has appeared on The Today Show and America's Got Talent.

References

External links

• The Michael Fund (United States)
• AMC Support (United States)
• Women for AMC Awareness
• The Arthrogryposis Group (United Kingdom)