Congenital mirror movement disorder is a condition in which intentional movements of one side of the body are mirrored by involuntary movements of the other side. For example, when an affected individual makes a fist with the right hand, the left hand makes a similar movement. The mirror movements in this disorder primarily involve the upper limbs, especially the hands and fingers. This pattern of movements is present from infancy or early childhood and usually persists throughout life, without other associated signs and symptoms. Intelligence and lifespan are not affected. The disease is Monarch Disease Ontology entry MONDO_0016558 (familial congenital mirror movements). Also known as: familial congenital controlateral synkinesia, hereditary congenital controlateral synkinesia, hereditary congenital mirror movements, isolated congenital controlateral synkinesia, isolated congenital mirror movements.