Arthrogryposis (AMC) describes congenital joint contracture in two or more areas of the body. It derives its name from Greek, literally meaning "curving of joints" (arthron, "joint"; grȳpōsis, late Latin form of late Greek grūpōsis, "hooking").Children born with one or more joint contractures have abnormal fibrosis of the muscle tissue causing muscle shortening, and therefore are unable to perform active extension and flexion in the affected joint or joints.AMC has been divided into three groups: amyoplasia, distal arthrogryposis, and syndromic. Amyoplasia is characterized by severe joint contractures and muscle weakness. Distal arthrogryposis mainly involves the hands and feet. Types of arthrogryposis with a primary neurological or muscle disease belong to the syndromic group. Signs and symptoms
Often,  every joint in a patient with arthrogryposis is  affected; in 84% all limbs are involved, in 11% only the legs, and in 4% only the arms are involved. Every joint in the body, when affected, displays typical signs and symptoms:  for example, the shoulder (internal rotation); wrist (volar and ulnar); hand (fingers in fixed flexion and thumb in palm); hip (flexed, abducted and externally rotated, frequently dislocated); elbow (extension and pronation) and foot clubfoot and less commonly congenital vertical talus.Range of motion can be different between joints because of the different deviations. Some types of arthrogryposis like amyoplasia have a symmetrical joint/limb involvement, with normal sensations.
Congenital Zika syndrome (CZS), may occur when there is vertical transmission of the Zika virus to the fetus. Myasthenia gravis of the mother leads also in rare cases to arthrogryposis. The major cause in humans is fetal akinesia, however, this is disputed lately. Intrinsic factors
Arthrogryposis could also be caused by intrinsic factors. This includes molecular, muscle- and connective tissue development disorders or neurological abnormalities. Molecular basis
Research has shown that there are more than 35 specific genetic disorders associated with arthrogryposis. Most of those mutations are missense, which means the mutation results in a different amino acid. Other mutations that could cause arthrogryposis are: single gene defects (X-linked recessive, autosomal recessive and autosomal dominant), mitochondrial defects and chromosomal disorders (for example: trisomy 18). This is mostly seen in distal arthrogryposis. Mutations in at least five genes (TNN12, TNNT3, TPM2, MYH3 and MYH8) could cause distal arthrogryposis. There could be also connective tissue, neurological or muscle development disorders. Muscle and connective tissue development disorders
Loss of muscle mass with an imbalance of muscle power at the joint can lead to connective tissue abnormality. This leads to joint fixation and reduced fetal movement. Also muscle abnormalities could lead to a reduction of fetal movement. Those could be: dystrophy, myopathy and mitochondrial disorders. This is mostly the result of abnormal function of the dystrophin-glycoprotein-associated complex in the sarcolemma of skeletal muscles.