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

SNCA gene

The SNCA gene provides instructions for making alpha-synuclein, a protein abundant in the brain that is critical for normal neuronal communication and function.

Normal Function

The SNCA gene provides instructions for making a protein called alpha-synuclein. This protein is abundant in the brain, particularly at the tips of nerve cells (neurons) in structures called presynaptic terminals. These terminals release chemical messengers called neurotransmitters from compartments known as synaptic vesicles, which is essential for relaying signals between neurons.

While its exact function is not fully understood, alpha-synuclein is believed to help maintain an adequate supply of synaptic vesicles and may regulate the release of dopamine, a neurotransmitter critical for controlling movement. It may also assist in the movement of microtubules, which help cells maintain their shape.

Health Conditions Related to Genetic Changes

Multiple system atrophy

Common variations in the SNCA gene are associated with an increased risk of multiple system atrophy, a progressive disorder affecting movement, balance, and the autonomic nervous system. These variations involve changes to a single DNA building block. It is currently unclear if these changes alter alpha-synuclein function or how they influence disease risk across different ethnic populations.

Dementia with Lewy bodies

At least six mutations in the SNCA gene cause dementia with Lewy bodies, characterized by intellectual decline, hallucinations, and movement problems. A hallmark of this condition is the presence of Lewy bodies—abnormal clusters of misshapen alpha-synuclein protein. These clusters impair neuron function and lead to cell death throughout the brain.

Parkinson's disease

At least 30 mutations in the SNCA gene are associated with early-onset Parkinson's disease. Alterations include:

  • Amino acid changes: Mutations such as Ala53Thr or Ala30Pro cause the alpha-synuclein protein to misfold into an incorrect 3-dimensional shape.
  • Gene duplication/triplication: Extra copies of the SNCA gene lead to an excess of alpha-synuclein protein.
  • Disease mechanism: Misfolded or excess alpha-synuclein clusters into Lewy bodies, which may kill dopamine-producing neurons in the substantia nigra. This loss of neurons weakens communication between the brain and muscles, resulting in the movement and balance issues characteristic of the disease.

Other Names for This Gene

  • alpha-synuclein
  • NACP
  • nonA-beta component of AD amyloid
  • PARK1
  • PARK4
  • PD1
  • synuclein, alpha (non A4 component of amyloid precursor)
  • SYUA_HUMAN

Frequently Asked Questions

While genetics set the baseline risk, several modifiable factors can help. Regular aerobic exercise, a Mediterranean‑style diet rich in antioxidants, adequate sleep, and avoidance of neurotoxins (e.g., pesticides, heavy metals) have all been linked to lower neurodegeneration rates. Cognitive training and social engagement may also support brain resilience. Discuss a personalized prevention plan with a neurologist or geriatrician.
Treatment focuses on symptom management. Dopaminergic medications (levodopa, dopamine agonists) can help with motor symptoms, but their benefit is often limited. Anticholinergics may reduce tremor, while selective serotonin reuptake inhibitors can address mood changes. For autonomic dysfunction, medications like fludrocortisone or midodrine can improve blood pressure regulation. Physical therapy, speech therapy, and occupational therapy are essential for maintaining function. Clinical trials targeting alpha‑synuclein aggregation are ongoing and may offer future options.
People with SNCA mutations often notice subtle motor changes before classic Parkinson's symptoms appear. Look for slight tremor at rest, stiffness in the limbs, or a gradual slowing of movements (bradykinesia). Non‑motor signs such as difficulty with fine tasks, changes in handwriting, or a new sense of fatigue can also be early clues. If you notice any of these, schedule a neurologic evaluation promptly to assess dopamine function and consider early therapeutic interventions.
Testing typically involves a blood or saliva sample sent for DNA sequencing of the SNCA gene. A positive result confirms a pathogenic variant that increases risk for Parkinson's, Lewy body dementia, or multiple system atrophy. For family members, a carrier test can determine if they also possess the mutation, guiding surveillance and lifestyle counseling. Genetic counseling is recommended to interpret results and discuss reproductive options.
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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