Handwringing in Rett syndrome: a normal developmental stage.

Handwringing, a characteristic clinical finding in Rett syndrome, appears typically after the loss of hand function. Available data suggest that original hand function never proceeds beyond elementary grasping. Handwringing and hand mouthing are normal developmental stages occurring at about 14 weeks of age in normal infants. The distressed behavior that characterizes the clinical onset of the disorder often turns attention away from the underlying severe apraxia. The confusion is further compounded by the fact that handwringing is also an elementary expression of stress in normal individuals.