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Dysautonomia, Familial

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Synonyms of Dysautonomia, Familial

Disorder Subdivisions

General Discussion

Familial dysautonomia is a rare genetic disorder of the autonomic nervous system (ANS) that primarily affects people of Eastern European Jewish heritage. It is characterized by diminished sensitivity to pain, lack of overflow tearing in the eyes, a decrease in the number of knob-like projections that cover the tongue (fungiform papillae), unusual fluctuations of body temperature, and unstable blood pressure. Symptoms of this disorder are apparent at birth. The autonomic nervous system controls vital involuntary body functions.

Symptoms

An infant born with familial dysautonomia typically has poor sucking ability, impaired swallowing reflexes, poor muscle tone (hypotonia), and/or abnormally low body temperature (hypothermia). Infants with this disorder may have cold hands and feet and experience unstable body temperature (from 94 to 108 degrees) during the course of infectious diseases. Profuse sweating and drooling may also occur. Crying without tears is one of the most striking symptoms of familial dysautonomia. Sometimes a lack of tears and insensitivity of the eyes to pain from foreign objects (corneal anesthesia) can lead to inflammation of the corneas and ulcerations in the eyes.

Children with familial dysautonomia have a decreased perception of pain and lack of sensitivity to hot and/or cold temperatures; this can result in unnoticed injuries to the skin. Unstable blood pressure is usually present in infants with familial dysautonomia. Blood pressure readings may vary greatly and may be abnormally high or low.

Other symptoms of familial dysautonomia may include the absence of the sense of taste, impaired speech, and/or red blotches on the skin that appear with emotional excitement. Approximately 40 percent of children with this disorder experience episodes of vomiting. Occasionally there may be skeletal defects, absence of tendon reflexes, stunted height, and/or repeated episodes of pneumonia due to the inhalation of food (aspiration).

By adolescence, 95 percent of individuals with familial dysautonomia have evidence of side-to side spinal curvature (scoliosis). In addition, they may experience increased sweating and an accelerated heart rate. A decreased awareness of pain makes it difficult for children with this disorder to be aware of injuries; bone fractures may go unrecognized. Other symptoms that may appear during adolescence include weakness, leg cramps, and/or difficulty concentrating. Personality changes may also occur including depression, irritability, inability to sleep (insomnia), and/or negativism.

Approximately 20 percent of adults with familial dysautonomia over 20 years of age develop kidney insufficiency. Neurological deterioration also appears and unsteadiness in walking may become more apparent at this age.

A medical test is available that can determine if an infant has familial dysautonomia. Histamine is injected under the skin and response is measured along nerve cell fibers (axon flare). A lack of response confirms the diagnosis of familial dysautonomia.

Causes

Familial dysautonomia is inherited as a recessive genetic trait. Human traits, including the classic genetic diseases, are the product of the interaction of two genes, one received from the father and one from the mother. In recessive disorders, the condition does not appear unless a person inherits the same defective gene for the same trait from each parent. If an individual receives one normal gene and one gene for the disease, the person will be a carrier for the disease, but usually will not show symptoms. The risk of transmitting the disease to the children of a couple, both of whom are carriers for a recessive disorder, is 25 percent. Fifty percent of their children risk being carriers of the disease, but generally will not show symptoms of the disorder. Twenty-five percent of their children may receive both normal genes, one from each parent, and will be genetically normal (for that particular trait). The risk is the same for each pregnancy.

Researchers have identified the gene that causes familial dysautonomia. Two mutations of the gene known as IKBKAP can cause FD. A carrier test is now available for all Ashkenazi Jews. Consult your local physician for details.

Affected Populations

Familial dysautonomia is a rare genetic disorder that affects males and females in equal numbers. This disorder primarily affects infants of Ashkenazi Jewish or Eastern European ancestry; approximately 1 in 30 people of East European Jewish ancestry are thought to be carriers of the defective gene that causes this disorder.

Related Disorders

Symptoms of the following disorders can be similar to those of familial dysautonomia. Comparisons may be useful for a differential diagnosis:

Biemond congenital and familial analgesia is a genetic disorder characterized by symptoms that are similar to those of familial dysautonomia. The symptoms of this disorder include insensitivity to pain, a diminished sense of temperature and touch, and the absence of tendon reflexes.

Congenital sensory neuropathy with anhidrosis (hereditary sensory and autonomic neuropathy or HSAN-IV) is a rare inherited disorder of the autonomic nervous system that is characterized by the loss of pain and temperature sensation and a lack of sweating. There may be wide variations in body temperature and recurrent episodes of unexplained high fevers. The symptoms of congenital sensory neuropathy with anhidrosis may initially be confused with familial dysautonomia.

Hereditary sensory neuropathy (HSAN II) is a rare inherited disorder characterized by insensitivity to pain, a diminished sense of temperature and touch, and the absence of tendon reflexes. Children with this disorder typically have decreased but not absent tear flow. The lack of sweating and the absence of abnormally low blood pressure upon standing (orthostatic hypotension) helps to distinguish this disorder from familial dysautonomia. (For more information on this disorder, choose "Hereditary Sensory Neuropathy" as your search term in the Rare Disease Database.)

"Dysautonomia," when used as a general medical term, refers to the abnormal functioning of the autonomic nervous system and can be combined with other words to describe specific conditions such as "diabetic cardiac dysautonomia" or "postganglionic cholinergic dysautonomia." There are many conditions characterized by the symptoms of dysautonomia. These should not be confused with the specific hereditary disorder of familial dysautonomia.

Standard Therapies

Drugs used to relieve the symptoms of familial dysautonomia include diazepam, metoclopramide, and chloral hydrate. Artificial tears may be needed to lubricate the eyes.

Physical therapy, chest physiotherapy, occupational therapy, feeding facilitation, and/or speech therapy may also be useful to alleviate the symptoms of familial dysautonomia.

People with familial dysautonomia may also benefit from a variety of other orthopedic and ocular (vision) aids.

Genetic counseling will be of benefit for patients with familial dysautonomia and their families.

Investigational Therapies

Information on current clinical trials is posted on the Internet at www.clinicaltrials.gov. All studies receiving U.S. government funding, and some supported by private industry, are posted on this government website.

For information about clinical trials being conducted at the National Institutes of Health (NIH) in Bethesda, MD, contact the NIH Patient Recruitment Office:

Tollfree: (800) 411-1222
TTY: (866) 411-1010
Email: prpl@cc.nih.gov.

For information about clinical trials sponsored by private sources, contact:
www.centerwatch.com

Felicia Axelrod, MD, of NYU Medical Center, is conducting several studies related to familial dysautonomia. For more information, interested individuals may wish to have their physicians contact:

Felicia B. Axelrod, MD
Dysautonomia Treatment and Evaluation Center
New York University Medical Center
530 First Ave., Suite 9Q
New York, NY 10016
(212) 263-7225

Dysautonomia, Familial Resources

NORD Member Organizations:

(To become a member of NORD, an organization must meet established criteria and be approved by the NORD Board of Directors. If you're interested in becoming a member, please contact Susan Olivo, Membership Manager, at solivo@rarediseases.org.)

Other Organizations:

References

TEXTBOOK
Online Mendelian Inheritance in Man, 10th Ed.: Victor A. McKusick, Editor: Johns Hopkins University Press, 1992. Pp. 768-769, 1345-1346.

Cecil Textbook of Medicine, 19th Ed.: James B. Wyngaarden, and Lloyd H. Smith, Jr., Editors; W.B. Saunders Co., 1990. Pp. 2246.

Principles of Neurology, 4th Ed.; Raymond D. Adams, M.D. and Maurice Victor, M.D., Editors; McGraw-Hill Information Services Company, 1989. Pp. 453, 1033, 1056.

Principles and Practices of Medical Genetics, 2nd Ed.: Allan E.H. Emery & David L. Rimoin, Editors; Churchill Livingston Publishers, 1990. Pp. 397- 441.

JOURNAL ARTICLES
Anderson SL, et al. Familial dysautonomia is caused by mutations of the IKAP gene. Am J Hum Genet. 2001;68:753-58.

Slaugenhaupt SA, et al. Tissue-specific expression of a splicing mutation in the IKBKAP gene causing familial dysautonomia. Am J Hum Genet. 2001;68:598-605.

Bar-On E, et al. Orthopaedic manifestations of familial dysautonomia. A review of one hundred and thirty-six patients. J Bone Joint Surg Am. 2000;11:1563-70.

Abrams P. Sundays in the park with Brittany. Nursing. 2000;8:49-51.

Report last updated: 2007/08/17 00:00:00 GMT+0