Episodic ataxia type 1

Episodic ataxia type 1 (EA1), also known as episodic ataxia with myokymia or Isaacs-Mertens syndrome variant, is a rare inherited neurological condition that causes sudden, brief episodes of poor coordination and balance (called ataxia). These episodes can last from seconds to a few minutes and may happen many times a day. Between episodes, many people experience continuous muscle rippling or twitching under the skin, especially around the eyes and hands — this is called myokymia. EA1 is caused by changes (mutations) in the KCNA1 gene, which controls how potassium moves in and out of nerve cells. When this gene does not work properly, nerve signals fire incorrectly, leading to the symptoms described above. Episodes of poor coordination are often triggered by sudden movement, exercise, stress, or being startled. During an episode, a person may feel unsteady, have slurred speech, experience muscle stiffness, or feel generally off-balance. Some people also have seizures. The condition usually begins in childhood or early adolescence and continues throughout life, though the severity varies greatly from person to person. There is no cure for EA1, but symptoms can often be managed with medication. The drug acetazolamide (a carbonic anhydrase inhibitor) is commonly used and helps reduce the frequency and severity of episodes in many patients. Some people also benefit from other medications such as carbamazepine or phenytoin. With proper treatment, many people with EA1 are able to live relatively normal lives, though ongoing medical monitoring is important.

Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.

Bring these to your next appointment

• Q1.What is the best medication for my specific situation, and what are the possible side effects?,How often should I expect episodes, and what can I do to reduce how often they happen?,Are there any activities or jobs I should avoid because of my condition?,Should other family members be tested for EA1 since it runs in families?,What should I do — or what should my caregiver do — when an episode happens?,Is there any research or clinical trial I could participate in?,How will this condition change over time, and what should I watch for as I get older?

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