In addition, in many people, the disease may be relatively non-progressive and the tremor may be mild throughout life. The symptoms of essential tremor may begin at any age from childhood through late adulthood. However, onset is rare in childhood, and the incidence of ET increases with advancing age. The mean age of onset is about 45 years. Overall, the symptoms and the possibility of related functional disability tend to progress with increasing age.
Increased amplitude is associated with a decreased ability to manage fine, discrete motor tasks.
Therefore, physical and functional disability leading to handicap and social embarrassment may increase with advancing age. ET may occur sporadically or be inherited as an autosomal dominant trait. Gene penetrance is nearly complete by the age of 65 to 70 years. Because of decreased penetrance, many people may be unaware of other family members with ET and therefore these cases may appear to be sporadic. In this family, each generation tended to develop symptoms of the disease at an earlier age than those in previous generations, suggesting possible genetic anticipation.