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Episodic ataxia refers to a group of conditions that affect the central nervous system. It affects specific nerve fibers that carry messages to and from the brain in order to control body movement. The condition causes episodes of poor coordination and balance (ataxia). Episodes may last from a few seconds to several hours. During an episode, affected people may experience dizziness; nausea; vomiting; migraine headaches; impaired vision; slurred speech; and/or ringing in the ears (tinnitus). An attack may also cause seizures, muscle weakness, and/or paralysis of one side of the body (hemiplegia). Age of onset, symptoms and severity can vary. Some people have several attacks per day, while others may have one or two per year. Episodic ataxia may be caused by a mutation in any of several genes and is inherited in an autosomal dominant manner. In some cases, the genetic cause is unknown. Treatment may include medication that reduces or eliminates symptoms. In some cases, symptoms improve or go away on their own.
At least 8 types of episodic ataxia have been recognized (referred to as types 1 through 8), which are distinguished based on their age of onset, features, and/or genetic cause.
Source: GARD Last updated on 05-01-20
We suggest that you explore our episodic ataxia Web page for general information and links to other Web sites with information about episodic ataxias. We also suggest you contact the support organizations we have listed, as they may be able to provide or direct you to additional information about episodic ataxia type 5.
You can also find articles containing information about episodic ataxia type 5 through PubMed, a searchable database of biomedical journal articles. Although not all of the articles are available for free online, most articles listed in PubMed have a summary available. To obtain the full article, contact a medical/university library or your local library for inter-library loan. You can also order articles online through the publisher’s Web site. Using "episodic ataxia type 5" or "episodic ataxia" as your search term should help you locate articles. For tips on building your search or narrowing your results, you can view PubMed's Search Tutorial.
The National Library of Medicine (NLM) can help you find libraries in your area where you can get the full text of medical articles. The webpage also describes how you can get these articles through interlibrary loan and Loansome Doc (an NLM document-ordering service). You can search for libraries at the following link: http://nnlm.gov/members/. You can also contact the NLM toll-free at 1-888-346-3656.
You may also benefit from meeting with a genetic counselor or other genetics professional. Genetics professionals are a source of information for individuals and families regarding genetic conditions, treatment, inheritance, and genetic risks to other family members. More information about genetic consultations is available from Genetics Home Reference. To find a genetics clinic, we recommend that you contact your primary healthcare provider for a referral.
The following online resources can help you find a genetics professional in your community:
Last updated on 05-01-20
Episodic ataxia type 5 (EA5) is a rare sub-type of episodic ataxia. EA5 is reportedly characterized by recurrent attacks that last for several hours, accompanied by ataxia; vertigo; dysarthria; nystagmus; and/or epilepsy (seizures). The symptoms have been described as being similar to those of episodic ataxia type 2. However, symptoms of EA5 tend to begin later than in EA2, with a typical onset in the third or fourth decade of life.
EA5 is caused by a mutation in the CACNB4 gene. This gene gives the body instructions to make parts of calcium channels (particularly in the brain), which carry calcium ions into cells. The channels are important for a cell's ability to make and transmit electrical signals. In the brain, calcium channels play an essential role in communication between nerve cells (neurons). They help control the release of neurotransmitters, which pass signals between neurons. Researchers believe these channels are also involved in the survival of neurons and their ability to adapt over time. Mutations in the CACNB4 gene are thought to impair the function of calcium channels in the brain, but exactly how this results in the features of EA5 is poorly understood. Mutations in CACNB4 are also found in some people with generalized epilepsy and juvenile myoclonic epilepsy.
EA5 is inherited in an autosomal dominant manner. This means that having a mutation in only one copy of the responsible gene in each cell is enough to cause features of the condition. In some cases, an affected person inherits the mutated gene from an affected parent. In other cases, the mutation occurs for the first time in a person with no family history of the condition. When a person with a mutation that causes an autosomal dominant condition has children, each child has a 50% (1 in 2) chance to inherit that mutation. However, it has been suggested that not all people with a CACNB4 mutation will develop EA5. This phenomenon is called reduced penetrance. It has been estimated that roughly 70% of people with a mutation will develop EA5.
Unlike in some of the other types of episodic ataxia, the symptoms of EA5 are considered responsive to medical treatment with acetazolamide. The frequency of attacks decreases markedly on acetazolamide (i.e., it can prevent attacks), and increases if the medication is discontinued.
Last updated on 05-01-20
Stefan Kipfer and Michael Strupp. The Clinical Spectrum of Autosomal-Dominant Episodic Ataxias. Movement Disorders Clinical Practice. December 2014; 1(4):285-290
Last updated on 04-27-20
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