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FD Fact Sheet

In individuals with FD, a progressive neurogenetic disorder, the autonomic and sensory nervous systems malfunction. Symptoms vary, and may include insensitivity to pain, unstable blood pressure and body temperature, absence of overflow tears, frequent pneumonia, and poor growth. FD is often associated with a shortened lifespan. Individuals with FD suffer from episodes of cyclical vomiting accompanied by extremely high blood pressure and increased heart rate, sweating and fever. These �autonomic crises� are one of the most devastating symptoms of this disease, often requiring hospitalization.

Name of disease: familial dysautonomia (FD), also known as Riley-Day Syndrome
Carrier frequency in Ashkenazi Jews:
1 in 27
Carrier frequency in the general population:
Age of onset:

Symptoms: FD causes dysfunction of the autonomic and sensory nervous systems. It is a progressive disease. Symptoms and severity vary in each patient. Symptoms include:

  • Absence of overflow tears / corneal drying

  • Poor suck at birth

  • Drooling

  • Swallowing & feeding problems

  • Hypotonia / poor muscle tone

  • Short stature

  • Delayed developmental milestones: motor, language, social

  • Inappropriate temperature controls

  • Wide swings in blood pressure

  • Gastro-esophageal reflux

  • Frequent lung infections or pneumonias

  • Episodic vomiting

  • Decreased or no reaction to pain and temperature

  • Excessive sweating

  • Blotchy reddening of skin with excitement and/or feeding

  • Smooth tongue / lack of taste buds

  • Spinal curvature

  • Poor weight gain and growth

  • Impaired renal function

  • Osteoporosis and osteopenia

  • Fainting and cardiac arrhythmias

  • Sleep apnea

  • Restrictive lung disease


Average lifespan: Currently, the mean age of the FD population is approximately 15 years. By statistical projection, babies born with FD in 2006 have a 50% chance of surviving to 40 years of age. The major causes of death are the result of pulmonary complications or sudden death due to autonomic instability.

What is the basis of disease: Inefficient gene splicing results in decreased production of a vital protein called IKAP. This protein is an essential component of a complex that aids in expression of multiple other target genes that are critical for growth and development of the sensory and autonomic nervous systems as well as their function.

Treatment or management:  There is no cure for FD. Treatments are supportive and preventative. Supportive therapies include medications to maintain and regulate cardiovascular, respiratory, and gastrointestinal function. Surgical interventions include fundoplication, gastrostomy, spinal fusion, and tear duct cautery.  Various therapies are used to promote strength and speech development.

Carrier testing: Carrier testing is available for the two most common mutations. All patients have one or two copies of a single splicing mutation; over 99% of cases of FD in the Ashkenazi Jewish (AJ) population have two copies of this splicing mutation. A second mutation paired with the AJ splicing mutation accounts for all other cases in the AJ population. A third mutation from a non-Jewish parent, again paired with the AJ splicing mutation, is responsible for a single case of FD.

Other testing information: Carrier screening is based on DNA analysis. Screening is 99% accurate for the AJ population.

Current research: Research focuses on modifying the splicing defect in order to increase production of IKAP as well as to further understand the role of this vital protein.  Researchers are also constructing an FD mouse model to further this aim.  Clinical investigations include assessment of sleep physiology and assessment of molecular and functional biomarkers.

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