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$Title{Benign Essential Tremor}
$Subject{Benign Essential Tremor Hereditary Benign Tremor Presenile Tremor
Syndrome Familial Tremor}
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Copyright (C) 1986, 1990 National Organization for Rare Disorders, Inc.

140:
Benign Essential Tremor

** IMPORTANT **
It is possible the main title of the article (Benign Essential Tremor) is
not the name you expected.  Please check the SYNONYMS listing to find
alternate names and disorder subdivisions covered by this article.

Synonyms

     Hereditary Benign Tremor
     Presenile Tremor Syndrome
     Familial Tremor

General Discussion

** REMINDER **
The information contained in the Rare Disease Database is provided for
educational purposes only.  It should not be used for diagnostic or treatment
purposes.  If you wish to obtain more information about this disorder, please
contact your personal physician and/or the agencies listed in the "Resources"
section.


Benign Essential Tremor is a disorder of unknown cause which usually does not
result in serious disability.  This disorder mainly involves the upper
extremities.  While the onset may occur in either childhood or old age, young
adults are affected most frequently, with the mean age onset being forty-five.

Symptoms

The main symptom of Benign Essential Tremor is a rhythmical tremor which may
be either fine or coarse.  The tremor usually has a frequency of 4-12 times
per second when the affected part is in movement or voluntarily held in one
position.  (Parkinson's Disease tremors usually diminish or disappear
entirely with purposeful movement.)  The tremors mainly affect the upper
extremities and are aggravated by stress, anxiety, fatigue and cold
temperatures.  Relief from the tremors may be achieved by rest, sedation, or
the use of alcohol.  (The use of alcohol to relieve tremors should be
discouraged as it can lead to alcohol abuse.)  Speech may be involved and
there may be hyperhidrosis (excessive sweating).  The symptoms of this
disorder generally stabilize after a period of progression.

Causes

About half of Essential Tremor cases are considered sporadic, the other half
hereditary.  The cause of Benign Essential Tremor is not known.  The disorder
may be inherited as an autosomal dominant trait.  (Human traits including the
classic genetic diseases, are the product of the interaction of two genes for
that condition, one received from the father and one from the mother.  In
dominant disorders, a single copy of the disease gene (received from either
the mother or father) will be expressed "dominating" the normal gene and
resulting in appearance of the disease.  The risk of transmitting the
disorder from affected parent to offspring is 50% for each pregnancy
regardless of the sex of the resulting child.)

Affected Population

Males and females are affected equally with Benign Essential Tremor.

Therapies:  Standard

Tremor associated with Benign Essential Tremor may be diminished or
controlled by the use of medications such as phenobarbital, propranolol or
primidone which is often effective in reducing the tremor.  Rest may be
useful.  While alcohol can relieve the symptoms, its use can lead to alcohol
abuse and should be avoided.

Therapies:  Investigational

This disease entry is based upon medical information available through June
1990.  Since NORD's resources are limited, it is not possible to keep every
entry in the Rare Disease Database completely current and accurate.  Please
check with the agencies listed in the Resources section for the most current
information about this disorder.

Resources

For more information on Benign Essential Tremor, please contact:

     National Organization for Rare Disorders (NORD)
     P.O. Box 8923
     New Fairfield, CT  06812-1783
     (203) 746-6518

     International Tremor Foundation
     360 West Superior St.
     Chicago, IL  60610
     (312) 664-2344

     NIH/National Institute of Neurological Disorders & Stroke (NINDS)
     9000 Rockville Pike
     Bethesda, MD  20892
     (301) 496-5751
     (800) 352-9424

For genetic information and genetic counseling referrals, please contact:

     March of Dimes Birth Defects Foundation
     1275 Mamaroneck Avenue
     White Plains, NY  10605
     (914) 428-7100

     Alliance of Genetic Support Groups
     35 Wisconsin Circle, Suite 440
     Chevy Chase, MD  20815
     (800) 336-GENE
     (301) 652-5553

References

CECIL TEXTBOOK OF MEDICINE, 18th ed.:  James B. Wyngaarden, and Lloyd H.
Smith, Jr., Eds.:  W. B. Saunders Co., 1988.  P. 2146.

THE MERCK MANUAL 15th ed:  R. Berkow, et al:  eds; Merck, Sharp & Dohme
Research Laboratories, 1987.  P. 1417-18.