Persistent mirror movements: a clinical study of 17 children, adolescents and young adults.

The author reports a series of 17 cases of congenital mirror movements of the hands and forearms (and in a few cases the toes), but no other signs of gross neurological deviation. This is an uncommon disorder that often goes unrecognised. This slight but definite disability seems to persist largely unchanged at least into the late teens, and probably into adulthood. A hereditary background is suggested in about half of the cases. Various neuropsychiatric deficits were seen in combination with the mirror movements in about half the cases, as well as a high incidence of non-right-handedness. Although the clinical heterogeneity of the disorder was clear, the phenomenon of mirror movements was similar in all cases. Recent progress in understanding the pathophysiology of this disorder is reviewed.