Arthrogryposis multiplex congenita refers to a variety of conditions that involve congenital limitation of joint movement.
There are two major types of arthrogryposis multiplex congenita (AMC):
Amyoplasia (classic arthrogryposis): Multiple symmetric contractures occur in the limbs. Affected muscles are hypoplastic and have fibrous and fatty degeneration. Usually intelligence is normal. About 10% of patients have abdominal abnormalities (eg, gastroschisis, bowel atresia) due to a lack of muscle formation. Nearly all cases are sporadic.
Distal arthrogryposis: The hands and feet are involved, but the large joints are typically spared. Distal arthrogryposes are a heterogeneous group of disorders, many of which are associated with a specific gene defect in one of a number of genes that encode components of the contractile apparatus. Many distal arthrogryposes are transmitted as autosomal dominant disorders, but x-linked mutations are known.