Typically not. The jerky movements would need to be observed and several things evaluated by history, physical exam and blood tests. A consultation with a neurologist would be recommended.
Depends. Nervous system maturity progresses from top down & center out.Infants/toddlers are more prone to less refined movements and must look at their fingers to voluntarily grasp and release things.They often drop things & by the age they show interest in coloring cannot stay within the lines until older. Any random, large scale jerking would be unexpected and require evaluation.