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CACNA1A gene
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Gene

CACNA1A gene

The CACNA1A gene provides instructions for making calcium channels essential for nerve cell communication, and variants in this gene are linked to several neurological disorders.

Normal Function

The CACNA1A gene provides instructions for making calcium channels, which transport positively charged calcium ions across cell membranes. These channels are key to generating and transmitting electrical signals and are involved in cell-to-cell communication, muscle contraction, and gene regulation.

The gene provides instructions for the alpha-1 subunit of the CaV2.1 calcium channel, which forms the pore for calcium flow. These channels are abundant in Purkinje cells and granule cells in the cerebellum, where they control the release of neurotransmitters. The gene also produces a protein called alpha1-ACT (α1ACT), a transcription factor that helps control gene activity and is important for the development of neurons.

Health Conditions Related to Genetic Changes

Episodic ataxia

Variants in the CACNA1A gene can cause episodic ataxia type 2 (EA2), characterized by episodes of poor coordination, balance issues, and involuntary eye movements (nystagmus). These are loss-of-function variants that reduce CaV2.1 channel function, impairing neurotransmitter release in the brain.

Familial hemiplegic migraine

Variants in CACNA1A are linked to familial hemiplegic migraine type 1 (FHM1), which involves migraines with aura, including temporary numbness or weakness on one side of the body (hemiparesis). These are gain-of-function variants that increase CaV2.1 channel activity, leading to excessive neurotransmitter release. Certain variants, such as S218L, can cause life-threatening brain swelling (cerebral edema) and coma following minor head trauma.

Spinocerebellar ataxia type 6

Spinocerebellar ataxia type 6 (SCA6) results from an expansion of the CAG trinucleotide repeat in the CACNA1A gene (ranging from 20 to more than 30 repeats). This expansion impairs the function of the α1ACT transcription factor, preventing the survival of Purkinje cells in the cerebellum and leading to progressive ataxia, nystagmus, and impaired speech (dysarthria).

Sporadic hemiplegic migraine

Sporadic hemiplegic migraine presents with signs identical to FHM1 but occurs in individuals with no family history. These variants are acquired during a person's lifetime and increase CaV2.1 channel activity.

19p13.13 deletion syndrome

Individuals with 19p13.13 deletion syndrome are often missing one copy of the CACNA1A gene. This deletion is associated with features including macrocephaly, tall stature, intellectual disability, seizures, and ataxia.

Other disorders

Variants in the CACNA1A gene can also cause a form of developmental and epileptic encephalopathy, characterized by repeated seizures, developmental delays, intellectual disability, and weak muscle tone (hypotonia).

Other Names for This Gene

  • APCA
  • brain calcium channel 1
  • CAC1A_HUMAN
  • CACNL1A4
  • calcium channel, alpha 1A subunit
  • calcium channel, L type, alpha-1 polypeptide, isoform 4
  • calcium channel, voltage-dependent, P/Q type, alpha 1A subunit
  • CAV2.1
  • HPCA
  • SCA6
  • Voltage-gated calcium channel subunit alpha Cav2.1

Frequently Asked Questions

Both EA2 and FHM1 are typically inherited in an autosomal dominant pattern. This means that a person only needs to inherit one copy of the altered CACNA1A gene from one parent to develop the condition. If a parent has the condition, there is a 50% chance with each pregnancy that their child will also inherit the altered gene and develop the disorder.
EA2 primarily involves episodes of poor coordination, balance problems, and involuntary eye movements (nystagmus), often triggered by stress or exertion. FHM1, on the other hand, is characterized by migraines with aura, which can include temporary numbness, weakness on one side of the body (hemiparesis), or visual disturbances, and these symptoms typically precede the headache.
Individuals with certain CACNA1A variants, such as S218L, are at a significantly increased risk of life-threatening brain swelling (cerebral edema) and coma following even minor head trauma. It is crucial for these individuals to avoid activities that carry a risk of head injury and to seek immediate medical attention for any head trauma, no matter how minor it seems.
Yes, for both EA2 and FHM1, certain triggers can precipitate episodes. Common triggers for EA2 attacks include physical exertion, stress, excitement, caffeine, alcohol, and certain medications. For FHM1, triggers can be similar to other migraines, such as stress, lack of sleep, certain foods, bright lights, strong smells, and hormonal changes. Identifying and avoiding personal triggers is an important part of managing these conditions.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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