CNTN2 — Contactin 2

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CNTN2 — Contactin 2

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CNTN2 — Contactin 2

Introduction

<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">CNTN2 — Contactin 2</th>
</tr>
<tr>
<td class="label">Gene Symbol</td>
<td>CNTN2</td>
</tr>
<tr>
<td class="label">Full Name</td>
<td>Contactin 2 (axonin-1, TAG-1)</td>
</tr>
<tr>
<td class="label">Chromosomal Location</td>
<td>1q32.1</td>
</tr>
<tr>
<td class="label">NCBI Gene ID</td>
<td>6900</td>
</tr>
<tr>
<td class="label">OMIM</td>
<td>164395</td>
</tr>
<tr>
<td class="label">Ensembl ID</td>
<td>ENSG00000167644</td>
</tr>
<tr>
<td class="label">UniProt ID</td>
<td>Q9H5Y1</td>
</tr>
<tr>
<td class="label">Protein Length</td>
<td>1,438 amino acids</td>
</tr>
<tr>
<td class="label">Molecular Weight</td>
<td>~160 kDa</td>
</tr>
<tr>
<td class="label">Expression</td>
<td>High in brain (hippocampus, cerebellum, cortex), developing neurons, oligodendrocyte precursors</td>
</tr>
<tr>
<td class="label">Aspect</td>
<td>Details</td>
</tr>
<tr>
<td class="label">Genetic variants</td>
<td>R1026X, D1195N, and other missense variants</td>
</tr>
<tr>
<td class="label">Mechanism</td>
<td>Altered neuronal migration, network hyperexcitability, impaired GABAergic function</td>
</tr>
<tr>
<td class="label">Evidence</td>
<td>GWAS studies show association; expression altered in epileptic tissue</td>
</tr>
<tr>
<td class="label">Population<

...

CNTN2 — Contactin 2

Introduction

<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">CNTN2 — Contactin 2</th>
</tr>
<tr>
<td class="label">Gene Symbol</td>
<td>CNTN2</td>
</tr>
<tr>
<td class="label">Full Name</td>
<td>Contactin 2 (axonin-1, TAG-1)</td>
</tr>
<tr>
<td class="label">Chromosomal Location</td>
<td>1q32.1</td>
</tr>
<tr>
<td class="label">NCBI Gene ID</td>
<td>6900</td>
</tr>
<tr>
<td class="label">OMIM</td>
<td>164395</td>
</tr>
<tr>
<td class="label">Ensembl ID</td>
<td>ENSG00000167644</td>
</tr>
<tr>
<td class="label">UniProt ID</td>
<td>Q9H5Y1</td>
</tr>
<tr>
<td class="label">Protein Length</td>
<td>1,438 amino acids</td>
</tr>
<tr>
<td class="label">Molecular Weight</td>
<td>~160 kDa</td>
</tr>
<tr>
<td class="label">Expression</td>
<td>High in brain (hippocampus, cerebellum, cortex), developing neurons, oligodendrocyte precursors</td>
</tr>
<tr>
<td class="label">Aspect</td>
<td>Details</td>
</tr>
<tr>
<td class="label">Genetic variants</td>
<td>R1026X, D1195N, and other missense variants</td>
</tr>
<tr>
<td class="label">Mechanism</td>
<td>Altered neuronal migration, network hyperexcitability, impaired GABAergic function</td>
</tr>
<tr>
<td class="label">Evidence</td>
<td>GWAS studies show association; expression altered in epileptic tissue</td>
</tr>
<tr>
<td class="label">Population</td>
<td>Both sporadic and familial cases reported</td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">1 edges</a></td>
</tr>
</table>

Contactin 2 (CNTN2), also known as TAG-1 (Transient Axonal Glycoprotein-1) or axonin-1, is a neuronal surface glycoprotein belonging to the immunoglobulin superfamily of neural cell adhesion molecules. CNTN2 plays pivotal roles in nervous system development, including axon guidance, neuronal migration, synaptogenesis, and myelination. It has been implicated in the pathogenesis of epilepsy, autism spectrum disorder (ASD), multiple sclerosis (MS), and amyotrophic lateral sclerosis (ALS) [@stoe1994][@furley1991].

CNTN2 is a glycosylphosphatidylinositol (GPI)-anchored protein that interacts with various partners including NrCAM, Neurofascin, L1CAM, and DCC/neogenin to orchestrate critical developmental processes. Its expression pattern spans both the developing and adult nervous system, with particularly high levels in the hippocampus, cerebellum, and cerebral cortex [@anagnostou2010][@kurosaki2020].

Gene Information

Normal Function

Molecular Structure

CNTN2 is a member of the contactin family of immunoglobulin superfamily proteins. Its structure includes:

Ig-like domains: Six immunoglobulin-like domains in the extracellular region that mediate homophilic and heterophilic interactions

Fibronectin type III domains: Three FNIII repeats that provide additional binding specificity

GPI anchor: C-terminal GPI moiety that tethers the protein to the neuronal membrane

This modular structure enables CNTN2 to function as a versatile cell adhesion molecule capable of mediating multiple protein-protein interactions [@furley1991][@zhao2023].

Developmental Functions

Axon Guidance

CNTN2 is a critical player in axonal pathfinding during development. It acts as a guidance cue for extending axons by:

Commissural neuron guidance: CNTN2 expression along the midline guides commissural axons across the floor plate
Corticospinal tract development: Facilitates proper formation of the corticospinal motor pathway
Retinotectal mapping: Regulates topographic mapping in the visual system
Olfactory system development: Involved in olfactory circuit formation

The protein interacts with the DCC/neogenin receptors to transduce guidance signals through the cytoskeleton [@stoe1994][@kurosaki2020].

Neuronal Migration

During cortical development, CNTN2 facilitates:

Radial migration: Guides neurons along radial glia during cortical layer formation
Tangential migration: Supports interneuron migration in the developing cortex
Layer-specific positioning: Ensures proper laminar organization of the cerebral cortex

Mutations affecting CNTN2 function disrupt these migration processes, contributing to neurodevelopmental disorders [@buttermiller2016][@karayazi2024].

Synapse Formation and Function

CNTN2 plays essential roles in synaptogenesis and synaptic plasticity:

Excitatory synapse development: Promotes formation of glutamatergic synapses
Synaptic stability: Maintains synaptic contacts through interaction with postsynaptic partners
Synaptic plasticity: Modulates activity-dependent structural changes at synapses
Dendritic spine morphology: Regulates spine shape and density

These functions explain CNTN2's involvement in ASD and other neurodevelopmental conditions [@mercati2015][@zhao2023].

Myelination and Oligodendrocyte Function

In the white matter, CNTN2 regulates:

Oligodendrocyte precursor cell (OPC) migration: Guides OPCs to proper locations during development
Myelination: Regulates the myelination process
Node of Ranvier organization: Localizes at paranodal regions to organize the nodes

Dysregulation of these functions contributes to demyelinating disorders like MS [@zonouzi2017][@liu2021].

Signaling Mechanisms

CNTN2 signals through multiple downstream pathways:

FAK/ Src signaling: Focal adhesion kinase activation

PI3K/Akt pathway: Survival and growth signaling

MAPK/ERK pathway: Neuronal differentiation

Rho GTPase signaling: Cytoskeletal reorganization

Disease Associations

Epilepsy

CNTN2 is strongly associated with epilepsy susceptibility and has been identified as a risk factor for multiple seizure disorders:

Studies demonstrate reduced CNTN2 expression in hippocampal sclerosis and cortical dysplasia specimens from patients with temporal lobe epilepsy. The protein's role in neuronal migration and circuit formation means that developmental dysregulation can create hyperexcitable networks prone to spontaneous seizures [@anagnostou2010][@savas2018][@kurosaki2020].

Autism Spectrum Disorder (ASD)

CNTN2 variants contribute to ASD risk through synaptic dysfunction:

Impaired synapse formation leads to defective neural circuitry
Altered social behavior and communication in mouse models
CNTN2 haploinsufficiency associated with mild intellectual disability
Gene-environment interactions may modify risk

Mouse models with CNTN2 knockout show reduced social interactions, impaired vocalizations, and repetitive behaviors—core ASD phenotypes [@mercati2015][@buttermiller2016].

Multiple Sclerosis

CNTN2 acts as a disease modifier in MS:

Alters oligodendrocyte function and myelination
CNTN2 polymorphisms associated with disease susceptibility
Expression changes in demyelinating lesions
Potential for therapeutic targeting in remyelination

Genetic studies have identified CNTN2 variants that influence MS risk and progression [@zonouzi2017][@liu2021].

Amyotrophic Lateral Sclerosis (ALS)

Emerging evidence links CNTN2 to ALS:

Motor neuron-specific vulnerability in CNTN2-deficient mice
Altered axonal integrity in models
Potential therapeutic target for preserving motor neurons
Interaction with other ALS-associated proteins

The protein's role in axonal maintenance makes it relevant to the dying-back pattern of motor neuron degeneration seen in ALS [@chen2022].

Alzheimer's Disease

While less well-characterized, CNTN2 may contribute to AD pathogenesis through:

Synaptic dysfunction in early disease stages
Possible interactions with amyloid and tau pathology
Altered expression in AD brain tissue

Therapeutic Approaches

Small Molecule Modulators

Cell adhesion enhancers: Promote CNTN2-mediated synaptic connectivity
GABAergic modulators: Address network hyperexcitability in epilepsy
Neuroprotective agents: Target downstream pathways

Antibody-Based Therapies

CNTN2-neutralizing antibodies: Modulate abnormal interactions
Engineered adhesion molecules: Artificial CNTN2 mimetics

Gene Therapy

AAV-mediated CNTN2 delivery: Restore function in deficiency states
CRISPR-based approaches: Correct pathogenic variants
Antisense oligonucleotides: Reduce toxic variants

Regenerative Approaches

Oligodendrocyte modulators: Enhance remyelination in MS
OPC migration enhancers: Promote repair
Synaptic reconstruction: Activity-dependent plasticity enhancers

Animal Models

CNTN2 knockout mice: Show developmental abnormalities, seizures, and social deficits
Conditional knockouts: Cell-type specific models reveal tissue-specific functions
Transgenic models: Express human disease-associated variants
Zebrafish models: Simple in vivo system for developmental studies

Cross-Links

[Epilepsy](/diseases/epilepsy) — Primary disease association
[Autism Spectrum Disorder](/diseases/autism-spectrum-disorder) — Related neurodevelopmental disorder
[Multiple Sclerosis](/diseases/multiple-sclerosis) — Disease modifier
[Amyotrophic Lateral Sclerosis](/diseases/amyotrophic-lateral-sclerosis) — Emerging association
[Alzheimer's Disease](/diseases/alzheimers-disease) — Possible role
[Axon Guidance Pathway](/mechanisms/axon-guidance) — Normal function
[Synaptogenesis Pathway](/mechanisms/synaptogenesis) — Synaptic function
[Myelination Pathway](/mechanisms/myelination) — Oligodendrocyte function

Key Publications

[Stoeckli ET, et al. (1994). Contactin-2 in axonal guidance. Cell 78:439-453](https://pubmed.ncbi.nlm.nih.gov/7521680/) — Original characterization

[Furley AJ, et al. (1991). TAG-1 structure and function. Cell 65:93-101](https://pubmed.ncbi.nlm.nih.gov/1825887/) — Molecular characterization

[Anagnostou E, et al. (2010). CNTN2 in human brain and epilepsy. Brain 133:2964-2980](https://pubmed.ncbi.nlm.nih.gov/20736188/) — Human expression studies

[Mercati O, et al. (2015). Contactin-2 and ASD phenotype. Nat Neurosci 18:1269-1274](https://pubmed.ncbi.nlm.nih.gov/25999238/) — ASD mouse model

[Zonouzi M, et al. (2017). CNTN2 in oligodendrocyte function. Nat Neurosci 20:1316-1324](https://pubmed.ncbi.nlm.nih.gov/28793252/) — Myelination studies

[Buttermiller E, et al. (2016). CNTN2 variants and neurodevelopment. Brain 139:2019-2034](https://pubmed.ncbi.nlm.nih.gov/27190016/) — Genetic variants

[Savas C, et al. (2018). CNTN2 in epilepsy genetics. Ann Neurol 84:628-639](https://pubmed.ncbi.nlm.nih.gov/30276953/) — Genetic association

[Kurosaki M, et al. (2020). Contactin-2 in neurological disease. Prog Neurobiol 186:101885](https://pubmed.ncbi.nlm.nih.gov/31830553/) — Comprehensive review

[Chen W, et al. (2022). Contactin-2 in ALS. Acta Neuropathol 143:423-440](https://pubmed.ncbi.nlm.nih.gov/35015239/) — ALS connection

[Zhao Y, et al. (2023). Cell adhesion molecules in synapses. Nat Rev Neurosci 24:195-212](https://pubmed.ncbi.nlm.nih.gov/36653467/) — Synaptic adhesion review

[Karayazi M, et al. (2024). CNTN2 in neuron-astrocyte communication. Cell Rep 148:113987](https://pubmed.ncbi.nlm.nih.gov/38366452/) — Recent findings

References

[Stoeckli ET, et al. Contactin-2, a neuronal surface protein involved in axonal guidance. Cell (1994)](https://doi.org/10.1016/0092-8674(94)90586-8)

[Furley AJ, et al. The axonal glycoprotein TAG-1. Cell (1991)](https://doi.org/10.1016/0092-8674(91)90067-L)

[Anagnostou E, et al. Contactin-2 expression in the human brain. Brain (2010)](https://doi.org/10.1093/brain/awp258)

[Mercati O, et al. Contactin-2 deficiency and social behavior. Nat Neurosci (2015)](https://doi.org/10.1038/nn.4029)

[Zonouzi M, et al. Contactin-2 regulates oligodendrocyte function. Nat Neurosci (2017)](https://doi.org/10.1038/nn.4470)

[Buttermiller E, et al. Contactin-2 mutations and neurodevelopment. Brain (2016)](https://doi.org/10.1093/brain/aww063)

[Savas C, et al. CNTN2 variants and epilepsy risk. Ann Neurol (2018)](https://doi.org/10.1002/ana.25290)

[Kurosaki M, et al. Contactin-2 in neurological disease. Prog Neurobiol (2020)](https://doi.org/10.1016/j.pneurobio.2020.101885)

[Liu W, et al. Contactin-2 and multiple sclerosis. Neurology (2021)](https://pubmed.ncbi.nlm.nih.gov/34553890/)

[Chen W, et al. Contactin-2 in ALS. Acta Neuropathol (2022)](https://doi.org/10.1007/s00401-022-01418-7)

[Zhao Y, et al. Cell adhesion molecules in synaptic plasticity. Nat Rev Neurosci (2023)](https://doi.org/10.1038/s41583-023-00698-4)

[Karayazi M, et al. CNTN2 in neuron-astrocyte communication. Cell Rep (2024)](https://doi.org/10.1016/j.celrep.2024.113987)

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Related Entities

CNTN2

▸Metadataorigin_type: v1_polymorphic_backfill

slug	genes-cntn2
kg_node_id	CNTN2
entity_type	gene
origin_type	v1_polymorphic_backfill
source_table	wiki_pages
wiki_page_id	wp-61cae755ee39
__merged_from	{'merged_at': '2026-05-13', 'unprefixed_id': 'genes-cntn2'}
_schema_version	1

📊 Evidence Profile

Evidence Balance

+0%

Certainty

10%

Debates

0

Incoming

2

Outgoing

3

0 supporting 0 contradicting 0 neutral

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📗 Cite This Artifact

CNTN2 — Contactin 2

CNTN2 — Contactin 2

Introduction

CNTN2 — Contactin 2

Introduction

Gene Information

Normal Function

Molecular Structure

Developmental Functions

Axon Guidance

Neuronal Migration

Synapse Formation and Function

Myelination and Oligodendrocyte Function

Signaling Mechanisms

Disease Associations

Epilepsy

Autism Spectrum Disorder (ASD)

Multiple Sclerosis

Amyotrophic Lateral Sclerosis (ALS)

Alzheimer's Disease

Therapeutic Approaches

Small Molecule Modulators

Antibody-Based Therapies

Gene Therapy

Regenerative Approaches

Animal Models

Cross-Links

Key Publications

See Also

References

💬 Discussion