Autoimmunity in Patients With GAD-Ab and Their Relatives (FamilyGAD)

Civil Hospices of Lyon

Status: Unknown

Conditions: Organ-specific Autoimmune Diseases; Neurological Syndromes With GAD-Ab

Study type: Observational

Funder types: Other

Identifiers

NCT04104620

FamilyGAD

Details and patient eligibility

About

A group of poorly studied immune-mediated neurological syndromes are associated with antibodies against glutamic-acid decarboxylase (GAD-Ab). GAD is the rate-limiting enzyme for the synthesis of gamma aminobutyric acid (GABA) from glutamate and is expressed by inhibitory neurons of the central nervous system. Neurological syndromes with anti-GAD antibodies (GAD-Ab) are often non-paraneoplastic. They mainly include limbic encephalitis (LE), cerebellar ataxia (CA) and stiff-person syndrome (SPS). Although the pathogenic role of GAD-Ab is controversial, most patients have high serum levels and GAD-Ab are also detected in the cerebrospinal fluid (CSF) along with other inflammatory abnormalities such as oligoclonal bands. GAD-Ab may also be present in the serum of T1DM patients, as pancreatic beta cells also express GAD, but usually at much lower titers than those of neurological patients. Organ-specific autoimmune diseases, such as T1DM and autoimmune thyroid disease, are common among patients with GAD-Ab and neurological syndromes and in their relatives, suggesting a shared genetic predisposition to autoimmune disorders. This is also supported by family reports of neurological syndromes with GAD-Ab and some HLA associations described in SPS.

The aim of this study is to describe the different autoimmune organ-specific diseases present in patients with GAD-Ab and their relatives, along with to identify families with higher aggregation of autoimmune diseases and establish potential ways of inheritability.

Full description

A group of poorly studied immune-mediated neurological syndromes are associated with antibodies against glutamic-acid decarboxylase (GAD-Ab). GAD is the rate-limiting enzyme for the synthesis of gamma aminobutyric acid (GABA) from glutamate and is expressed by inhibitory neurons of the central nervous system. Neurological syndromes with anti-GAD antibodies (GAD-Ab) are often non-paraneoplastic. They mainly include limbic encephalitis (LE), cerebellar ataxia (CA) and stiff-person syndrome (SPS). Although the pathogenic role of GAD-Ab is controversial, most patients have high serum levels and GAD-Ab are also detected in the cerebrospinal fluid (CSF) along with other inflammatory abnormalities such as oligoclonal bands. GAD-Ab may also be present in the serum of T1DM patients, as pancreatic beta cells also express GAD, but usually at much lower titers than those of neurological patients. Organ-specific autoimmune diseases, such as T1DM and autoimmune thyroid disease, are common among patients with GAD-Ab and neurological syndromes and in their relatives, suggesting a shared genetic predisposition to autoimmune disorders. This is also supported by family reports of neurological syndromes with GAD-Ab and some HLA associations described in SPS.

The aim of this study is to describe the different autoimmune organ-specific diseases present in patients with GAD-Ab and their relatives, along with to identify families with higher aggregation of autoimmune diseases and establish potential ways of inheritability.

Enrollment: 100 estimated patients

Sex: All

Ages: 18+ years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Patient with a well-known neurological syndrome associated with Gad-Ab (LE, CA, SPS)
• Patient with an CSF positive for GAD-Ab;
• Patient witn an Age > 18 years old.

Exclusion criteria

• Patient with absence of complete clinical data.
• Patient with CSF not tested or negative for GAD-Ab

Trial design

100 participants in 1 patient group

patients with neurological syndromes and GAD-Ab

Description:

This is a non-interventional study involving clinical data already stored in the database of the Centre de référence des syndromes neurologiques paranéoplasiques et encéphalites auto-immunes, or collected by the referral physicians the day of ordinary consultations. No biological sample is necessary to perform this study.