SNP Shot: Genomic Insights

Episodic ataxia refers to a set of neurological disorders characterized by impaired movement and coordination. The hallmark of these conditions is recurrent episodes of ataxia, marked by poor balance and coordination. During these episodes, individuals may also experience vertigo (dizziness), nausea, vomiting, migraines, blurred or double vision, slurred speech, and tinnitus (ringing in the ears). In some cases, seizures, muscle weakness, or hemiplegia (paralysis on one side of the body) can also occur.

Beyond the primary symptoms, myokymia (muscle cramping, stiffness, or continuous muscle twitching visible under the skin) and nystagmus (rapid, involuntary eye movements) may manifest either during or between episodes.

The onset of episodic ataxia can range from early childhood to adulthood. Episodes can be triggered by various environmental factors including stress, caffeine, alcohol, certain medications, physical exertion, and illness. The length and frequency of these episodes vary significantly, ranging from seconds to days and from multiple times daily to just a few times a year. While some individuals are symptom-free between episodes, others may experience persistent ataxia that can worsen over time.

Some children with episodic ataxia may exhibit delays in speech or motor skill development, such as standing and walking. Learning difficulties may also be present.

At least 11 distinct types of episodic ataxia have been identified, differentiated by their specific symptoms, age of onset, episode duration, and underlying genetic causes.

Inheritance:

Episodic ataxia typically follows an autosomal dominant inheritance pattern. This means that only one copy of the mutated gene in each cell is enough to cause the condition. In some instances, an affected individual inherits the altered gene from a parent who also has the condition. However, new genetic mutations can also occur, leading to cases where there is no family history of episodic ataxia.