There is overlap between essential tremor, which may occur as an isolated case but may also run in families, and familial tremor, which affects more than one person in a family. Tremors can affect people at any age, but they are most common in older people.
A familial tremor is usually a relatively benign condition, affecting movement or voice quality but seldom having any other effects. It involves a rhythmic, moderately rapid tremor (shaking) of voluntary muscles.
Purposeful movements may make the tremors worse. There may be difficulty holding or using small objects (such as eating or writing utensils). Emotional stress may also increase the tremors.
Over time, the tremors may affect the hands, arms, head, voice box (larynx), eyelids, or other muscles, but they rarely involve the legs or feet. In children, these tremors are usually limited to the hands and rarely require treatment.
The exact cause is unknown, but the fact that it is inherited suggests a genetic cause. It is usually dominant, which means about 50% of an affected person's children will be affected.
If you inherit one copy of the gene from either parent, you will have the disorder.
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