Arthrogryposis

Arthrogryposis, more fully arthrogryposis multiplex congenita, is a congenital condition in which a person is born with contractures, meaning stiffened, limited-motion joints, affecting two or more areas of the body. Its name comes from Greek words meaning curved or hooked joints. The underlying cause is a lack of normal movement in the womb, which lets the tissue around a joint thicken and shorten instead of developing the flexibility that regular fetal movement produces; more than thirty distinct genetic disorders have been linked to the condition, along with non-genetic causes such as too little amniotic fluid, restricted blood supply to the fetus, maternal fever, and viral infections including Zika virus. Doctors group cases into three broad categories: amyoplasia, the most common single form, marked by severe symmetrical contractures and muscle weakness; distal arthrogryposis, which mainly affects the hands and feet; and syndromic arthrogryposis, where the joint contractures accompany a wider neurological or muscular disease. In most severe cases the nervous system itself is implicated. The condition is present at birth and does not worsen over time, and treatment centers on physical therapy, splinting, and in some cases corrective surgery to improve joint mobility.