Definition of Essential tremor

Essential tremor: Uncontrollable shaking (tremor) of the hands and head and sometimes other parts of the body. Essential tremor is the most common of all movement disorders and is estimated to affect 3 to 4 million people in the US. In more than half of cases, essential tremor is inherited in an autosomal dominant manner. In 1997, the ETM1 gene (also called FET1) was mapped to chromosome 3 in a study of Icelandic families while another gene, called ETM2, was mapped to chromosome 2 in a large American family of Czech descent. That two genes for essential tremor have been found on two different chromosomes demonstrates that mutations in various genes may lead to essential tremor. The mainstays of treatment are drugs such as propranolol and primidone.

Samuel Adams (1722-1803), the American Revolutionist and brewer, suffered from a tremor. The tremor affected his hands, head, and voice. Although mild, the tremor was already manifest when Adams was in his early forties. A prolific writer, Adams experienced progressive difficulty with writing in his fifties and early sixties. By age 71, he was forced to dictate all of his correspondence. His tremor was familial, affecting his daughter Hannah and her children. It has been suggested that Adams suffered from one of the earliest documented cases of essential tremor.

Also known as familial tremor, heredofamilial tremor, and hereditary essential tremor. See: ETM1; ETM2.