Is there an illness involving involuntary movements in the hand?

Involuntary hand mov. Involuntary movements of hands only and no other part of body, can be due to essential tremors.Having said that it can be a sumptom of other neurological disorders in which involuntary movements of hands are only part of their symptoms, likedystonia, huntington disease, multiple system atrophy, myoclonus, huntington diesease and others.