Familial dysautonomia (FD) is a rare genetic condition affecting the nervous system. It impacts the development and survival of certain nerve cells that influence involuntary actions in the body.

FD is a rare type of dysautonomia.

Dysautonomia is a group of medical conditions that result in problems with involuntary functions, such as breathing, digestion, and regulating blood pressure. The term “familial” refers to the fact that a person inherits FD from their biological parents.

Read on to learn more about familial dysautonomia, including its causes, symptoms, and treatments.

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FD, also known as Riley-Day syndrome and hereditary sensory and autonomic neuropathy 3, is a rare genetic condition that affects the autonomic and sensory nervous systems. It is a very rare type of dysautonomia.

This term describes conditions that affect the functioning of the autonomic nervous system (ANS), a complex network of cells that controls the body’s internal state and regulates unconscious tasks such as:

The characteristic symptoms of FD occur due to a person with the condition being unable to sense information coming from inside their body.

FD predominately affects people of Ashkenazi Jewish descent, with a frequency of approximately 1 in 3,700 amongst people with this ancestry. Roughly 1 in 36 people of Ashkenazi Jewish descent are carriers of the condition.

Outside this population, FD is extremely rare. Evidence suggests that there are only 350 people currently living with the condition worldwide.

Familial dysautonomia occurs due to an alteration in the ELP1 gene, formally known as the IKBKAP gene, located on chromosome 9.

This gene provides instructions for a protein called IKAP, which plays a role in developing and maintaining nerve cells, particularly those in the autonomic and sensory systems.

The variation in the ELP1 gene results in a deficiency of IKAP, which affects the number of functioning nerve fibers. As a result, a person with FD experiences reduced sensations of pain, touch, temperature, and taste.

A person inherits the gene variation in an autosomal recessive manner. This means an affected individual must inherit two copies of the gene alteration, one from each parent, to develop the condition. Individuals who carry only one copy of the mutated gene are known as “carriers” and typically do not exhibit symptoms.

Experts suggest familial dysautonomia occurs almost exclusively in people of Ashkenazi Jewish descent. It is extremely rare outside of this population.

FD can present with a wide range of symptoms that affect various aspects of an individual’s health and well-being.

The condition primarily affects the ANS, which regulates involuntary bodily functions, and the sensory nervous system, responsible for transmitting sensory information.

Some of the common symptoms of FD may include:

  • abnormalities of the pupils
  • an inability to produce tears
  • difficulty feeding in infancy
  • growth delays
  • problems with sweating
  • reduced reactions
  • a reduced ability to feel pain
  • problems with blood pressure
  • lack of coordination
  • behavioral problems
  • issues with walking
  • low muscle tone
  • susceptibility to respiratory infections
  • scoliosis
  • autonomic crisis, which involves periods of very high blood pressure and heart rate that accompany uncontrollable vomiting or retching

Diagnosis of FD will typically involve a combination of clinical evaluation, genetic testing, and family history assessment.

However, diagnosing it can be challenging as it is an “orphan disease.” This means it affects fewer than 200,000 people nationwide.

A doctor may suggest genetic testing if an infant presents with characteristic signs of FD, such as feeding difficulties, unusual autonomic responses, a smooth tongue, and an inability to produce tears.

This form of testing will be able to detect the presence of an alteration in the ELP1 gene to confirm the diagnosis.

Currently, there is no cure for FD, and treatments primarily focus on managing symptoms and improving quality of life.

A multidisciplinary approach involving various medical specialists is typically necessary to address the specific needs of those with FD.

For example, treatment options may include:

Ongoing research is investigating methods to help individuals with FD produce sufficient amounts of the IKAP protein.

FD can be fatal in childhood and adolescence. However, with improvements in medical care, life expectancy is increasing, and roughly half of people with the condition live to the age of 30.

Familial dysautonomia (FD) is a rare type of dysautonomia. This term refers to a group of conditions that affect the functioning of the autonomic nervous system.

FD occurs when a person inherits a variation in the ELP1 gene from both parents. This alteration affects the amount of IKAP protein a person produces. This protein plays a role in the development of nerve cells.

Characteristic symptoms of the condition include reduced control of blood pressure, body temperature, and breathing. FD is most prevalent in people of Ashkenazi Jewish ancestry, and genetic testing can confirm a diagnosis. There is currently no cure for FD, so treatment focuses on managing symptoms.