Alternative Names
benign essential tremor; familial tremor; hereditary essential tremor
Symptoms & Characteristics
Essential tremor is a disorder of the nervous system that causes tremors, especially in the hands. It involves tremor without any other signs or symptoms, and is distinguished from tremor that results from other disorders or known causes, such as tremors seen with Parkinson's disease or head trauma.
Essential tremor usually occurs when the muscles are opposing gravity (such as when the hands are extended) and worsens with movement. This type of tremor is usually not evident at rest.
In addition to the hands and arms, muscles of the trunk, face, head and neck may also exhibit tremor in this condition; however, the legs and feet are not usually involved. Head tremor may appear as a "yes-yes" or "no-no" movement while the affected individual is seated or standing. In some affected individuals, voice quality may be affected.
Essential tremor is not considered a dangerous or debilitating condition. It does not shorten the lifespan. However, if severe, it may interfere with fine motor skills such as using eating utensils, writing, shaving, or applying makeup. Symptoms of essential tremor may be aggravated by emotional stress, fatigue, hunger, caffeine, cigarette smoking or extremes of temperature.
Essential tremor may appear at any age, but is most frequent in the elderly. Some studies have suggested that affected people may have a higher than average risk of developing Parkinson's disease, sensory problems (such as hearing loss), or other neurological conditions. Others suggest that essential tremor may be associated with increased longevity.
Treatment
The management and treatment of essential tremor depends on the severity of symptoms.
How Common Is It?
Essential tremor is a common disorder, affecting millions of Americans.
Estimates of its prevalence vary widely because several other disorders, as well as certain medications and other factors, can result in similar tremors. Essential tremor may affect as many as 14% of people over 65 years old.
Genetics & Inheritance
Essential tremor is a complex, multifactorial condition. Several genes are believed to influence a person's risk to develop this condition. Environmental factors may also be involved.
- Some studies have found the DRD3 gene to be associated with essential tremor.
- In other studies, the gene HS1BP3 has also been associated with essential tremor. An HS1BP3 variant has been identified in some families affected by essential tremor, but it has also been found in unaffected people. It is unknown what relationship, if any, this genetic variation may have to the signs and symptoms of this condition.
Essential tremor can run in families, but the inheritance pattern varies. In most affected families, essential tremor appears to be inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. In other families, the inheritance pattern is unclear.
Essential tremor may also appear in people with no family history of the disorder.
Genetic Testing
Clinical genetic testing for the genes known to be associated with essential tremor may be available through an in person genetic consultation for people who are considered at risk. Use our find a genetic professional directory to locate a trained genetic professional in your area.
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