The SNCA (Synuclein Alpha) gene encodes alpha-synuclein, a protein critically involved in synaptic function and implicated in the pathogenesis of Parkinson's disease and related neurodegenerative disorders.
| Property | Value |
|----------|-------|
| Gene Symbol | SNCA |
| Full Name | Synuclein Alpha |
| Chromosomal Location | 4q22.1 |
| NCBI Gene ID | 6622 |
| OMIM | 163890 |
| Ensembl ID | ENSG00000145335 |
| UniProt ID | P37840 |
| Inheritance | Autosomal Dominant |
Alpha-synuclein is a natively unfolded protein primarily localized to presynaptic terminals. Its normal functions include:
- Synaptic vesicle regulation: Alpha-synuclein modulates synaptic vesicle pooling and neurotransmitter release
- Membrane interaction: The protein binds to lipid membranes, potentially regulating vesicle trafficking
- Antioxidant function: Alpha-synuclein may protect neurons from oxidative stress
- Chaperone activity: The protein has molecular chaperone properties, aiding protein folding
Alpha-synuclein exists in multiple forms:
- Monomeric: Unfolded, cytosolic form
- Oligomeric: Small aggregates (toxic intermediate)
- Fibrillar: Forms Lewy bodies in disease states
- Parkinson's Disease (PD) - SNCA was the first gene linked to familial PD
- Lewy Body Dementia (DLB) - Characterized by Lewy bodies containing alpha-synuclein
- Multiple System Atrophy (MSA) - Another synucleinopathy with oligodendroglial inclusions
- Parkinson's Disease with Dementia
| Mutation |
Effect |
Phenotype |
Discovery |
| A53T (p.Ala53Thr) |
Accelerated aggregation |
Early-onset PD (familial) |
Polymeropoulos et al., 1997 |
| A30P (p.Ala30Pro) |
Reduced membrane binding |
Familial PD |
Krüger et al., 1998 |
| E46K (p.Glu46Lys) |
Enhanced aggregation |
Familial PD with dementia |
Zarranz et al., 2004 |
| H50Q |
Modified aggregation |
PD |
Appel-Cresswell et al., 2013 |
| G51D |
Altered aggregation |
PD with brainstem pathology |
Lesage et al., 2013 |
| A53E |
Altered aggregation |
MSA-like phenotype |
Pasanen et al., 2014 |
- SNCA duplication: Causes autosomal dominant PD
- SNCA triplication: Causes early-onset PD with rapid progression (Parkinsonism-Dementia Complex of Guam)
- Lewy body formation: Abnormal aggregation of alpha-synuclein into insoluble fibrils
- Synaptic dysfunction: Loss of normal protein function disrupts neurotransmitter release
- Mitochondrial dysfunction: Alpha-synuclein toxicity affects mitochondrial quality control
- Neuroinflammation: Aggregates activate microglia, promoting neuroinflammation
Alpha-synuclein is predominantly expressed in the nervous system:
- Substantia nigra - Dopaminergic neurons (most vulnerable in PD)
- Cortex - Especially in regions affected in DLB
- Hippocampus - Involved in memory impairment
- Hypothalamus and amygdala
- Peripheral nervous system - Including enteric nervous system
Expression is highest in presynaptic terminals of excitatory neurons.
- Immunotherapies: Anti-alpha-synuclein antibodies (e.g., cinpanemab, prasinezumab)
- Small molecule inhibitors: Compounds preventing aggregation
- Gene therapy: siRNA approaches to reduce SNCA expression
- Vaccination: Active immunization against alpha-synuclein
- Protein clearance enhancement: Boosting autophagy and proteasome function
- Mitochondrial protection: Targeting alpha-synuclein-induced mitochondrial defects
- Synaptic restoration: Compounds promoting synaptic function recovery
- ** biomarker development**: Alpha-synuclein as a diagnostic biomarker
- Polymeropoulos et al., Mutation in the alpha-synuclein gene identified in families with Parkinson's disease (1997)
- Spillantini et al., Alpha-synuclein in Lewy bodies (1997)
- Zarranz et al., The new mutation, E46K, of alpha-synuclein causes Parkinson and Lewy body dementia (2004)
- Bridi & Hirth, Mechanisms of alpha-Synuclein Induced Neurodegeneration in Parkinson's Disease (2018)
This section highlights recent publications relevant to this disease.