What is Anti-Contactin-associated protein-like 2 (CASPR2) and Why Does the Neural Zoomer Test for It?

Neuronal membrane adhesion protein

CASPR2 is a cell-surface protein found on neurons that helps organize ion channels and maintain stable electrical signaling. Measuring antibodies to CASPR2 can reveal immune activity against neuronal surface structures, offering insight into patterns of altered nerve signaling or sensory and cognitive symptoms.

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Anti-Contactin-associated protein-like 2 (CASPR2)

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About Anti-Contactin-associated protein-like 2 (CASPR2)

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About Anti-Contactin-associated protein-like 2 (CASPR2)

Overview and History

CASPR2 (Contactin-associated protein-like 2) is a large transmembrane cell-adhesion protein encoded by the CNTNAP2 gene. It is part of a family of neuronal membrane proteins that localize to specific axonal regions and interact with ion channel complexes, notably voltage-gated potassium channels. Functionally, CASPR2 helps cluster and stabilize channel proteins at axon domains to support orderly electrical conduction and synaptic communication. Clinical research has identified immune responses that target CASPR2 in some patients, making it a useful marker when exploring immune–neural interactions and disturbances in neuronal excitability.

Interpreting Highs and Lows

Elevated anti-CASPR2 antibody levels suggest immune activity directed at a neuronal surface protein involved in ion channel organization. This pattern can associate with symptoms related to altered nerve signaling, sensory changes, muscle excitability, or cognitive and behavioral shifts, but interpretation depends on timing, clinical findings, and other test results. Low or undetectable anti-CASPR2 levels indicate little to no circulating antibody activity against this target; however, absence of antibodies does not rule out other neuroimmune mechanisms, non-immune causes, or markers elsewhere on the Neural Zoomer panel. Always consider CASPR2 results alongside the full panel and clinical picture for a balanced interpretation.

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CASPR2 is included in the Neural Zoomer to detect immune responses against a neuronal surface protein that organizes ion channels and supports nerve signaling. Evaluating CASPR2 antibodies helps map surface-directed neuroimmune patterns and, when combined with other markers, refines assessment of sensory, cognitive, and neuromuscular profiles for more personalized diagnostic focus.

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Anti-Contactin-associated protein-like 2 (CASPR2) FAQs

What is Anti-Contactin-associated protein-like 2 (CASPR2) and why is it important?

CASPR2 is a protein on nerve cells that helps position ion channels for proper electrical signaling. When the immune system makes antibodies that target CASPR2, it can signal immune activity directed at neuronal surfaces. Measuring these antibodies helps providers understand whether surface-directed immune patterns might be affecting nerve signaling, sensation, or cognitive function.

What does it mean if my Anti-Contactin-associated protein-like 2 (CASPR2) levels are low?

Low or absent anti-CASPR2 antibodies generally mean there is no detectable immune response against this specific neuronal protein in the tested sample. That finding suggests CASPR2-directed immune activity is unlikely, but it does not exclude other immune targets or non-immune causes of symptoms. Clinicians interpret low CASPR2 results together with other Neural Zoomer markers and the overall clinical context.

What does it mean if my Anti-Contactin-associated protein-like 2 (CASPR2) levels are high?

Higher anti-CASPR2 levels indicate measurable immune activity against a neuronal surface protein involved in ion channel organization. This pattern can be associated with altered nerve signaling, sensory or cognitive changes, or increased neural excitability, but it requires correlation with symptoms and other tests. Elevated CASPR2 antibodies are one piece of the overall neuroimmune assessment and need clinical context for interpretation.

Why is CASPR2 included in the Neural Zoomer?

CASPR2 antibodies help reveal immune interactions at neuronal surfaces and ion channel complexes, areas that directly affect signaling and excitability. Including CASPR2 in the Neural Zoomer adds specificity for surface-directed neuroimmune patterns and complements other domains to support more targeted, personalized assessment.

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