What is arthrogryposis? Firstly it is also known as Arthrogryposis Multiplex Congenita, a rare congenital disorder that causes multiple joint contractures that causes muscle weakness and fibrosis. Arthrogryposis is a non-progressive disease. Arthrogryposis includes many different conditions. They Multiple Pterygium syndrome, Larsen syndrome and Freeman Sheldon syndrome. Some arthrogryposis conditions are mild whilst others involve problems with other body functions such as the brain, nervous system or muscles. Find a selection of official and unofficial medical sites listed below and visit the individual sites for more details and contacts.