CASPR2 Encephalitis Initial Symptoms

Study Overview
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Brief Summary
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Auto-immune encephalitides involve auto-antibodies targeting the central nervous system, and particularly the synapse and its structure, such as protein CASPR2. CASPR2 antibody-associated auto-immune encephalitides lead to an inflammation of the limbic system and generate focal temporal seizures and cognitive impairment. Most patients are initially hospitalized because of the temporal seizures (Joubert et al., JAMA Neurology 2016). However, many already show at that time cognitive impairment, which has failed to elicit the appropriate investigations, therefore delaying the diagnosis. The study will hence investigate precisely the initial, sometimes neglected, clinical symptoms and those leading to the diagnosis, in the cohort of patients suffering from a CASPR2 antibody-associated encephalitis, from the French reference center on paraneoplastic neurological diseases and autoimmune encephalitis. This way, the study aims to delineate the symptoms that should trigger suspicions of a CASPR2 antibody-associated encephalitis

Official Title
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Defining the Initial Clinical Symptoms and Characterizing Those Leading to the Discovery of CASPR2

Conditions
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CASPR2-Antibody, Encephalitis Autoimmune, Paraneoplastic Syndromes

Intervention / Treatment
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* Other: CASPR2 encephalitis


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Positive CASPR2-Ab in serum and/or CSF tested by immunohistochemistry on mouse brain slices and confirmed by cell-based assay (CBA) of HEK293 cells expressing CASPR2. Diagnosis and follow-up in France From 18 to unlimited age Exclusion Criteria: Patients CASPR2-IgG negative in serum and CSF Foreign follow-up

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| CASPR2 encephalitis<br>Cohort of patients with a CASPR2 antibody-associated auto-immune encephalitis. | Other: CASPR2 encephalitis<br>* Defining the initial clinical symptoms and those leading to the diagnosis of CASPR2 antibody associated encephalitis. For that, we will investigate the initial cognitive status, the initial neuropsychological investigations the clinical presentation of the first seizures, and the prodromes assessed by patients at the beginning of their disease. We will also look at the initial EEG records, in order to acknowledge whether the initial cognitive symptoms may be due to unseen seizures.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Initial cognitive impairment or clinical presentation of first epileptic seizures. | The retained information will depend on the very first declared symptom: if the patient first showed focal seizures, we will precise the clinical presentation of this seizure. On the other hand, if the patient first showed cognitive symptoms, we will best define this impairment. | 8 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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antibody ; auto-immune encephalitis ; paraneoplastic syndrome ; CASPR2