Arthrogryposis multiplex congenita in a monozygotic twin. An intrauterine lesion?

Arthrogryposis multiplex congenita is a specific, well-defined congenital deformity which primarily affects muscles of limbs resulting in secondary joint deformities. The aetiology is still uncertain. One of monozygotic twin brothers with classical arthrogryposis multiplex congenita is presented, proving that this specific condition is not genetically transmitted.