An observational study in Neuropathy Demyelinating, sponsored by Rennes University Hospital. Completed at 1 site in France. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2018-02-27.
Sponsored by Rennes University Hospital · Observational
Anti-MAG (Myelin Associated Glycoprotein) neuropathy is related to clonal B lymphocyte proliferation producing an monoclonal immunoglobulin (IgM) with anti-MAG activity. IgM may be a reflection of malignant lymphoproliferative syndrome (Waldenström disease) or, more often, monoclonal gammopathy of unknown significance.
The anti-MAG antibody has a direct toxicity on the myelin sheath of the peripheral nervous system responsible for a length-dependent demyelinating polyneuropathy. Clinically, this results in a sensitive, ataxic predominant polyneuropathy in the lower limbs, sometimes associated with a tremor of attitude and action tremor of the upper limbs.
Clonal B cells at the origin of IgM production may have acquired mutations affecting MYD88 (MYD88 L265P mutation) and CXCR4 (Whim-like CXCR4 mutation). The prevalence of the MYD88 L265P mutation is estimated to be 50% in monoclonal gammopathies of undetermined significance and more than 80% in Waldenström disease. CXCR4 Whim-like mutations are found in 40% of patients with Waldenström's disease.
No studies have reported the prevalence of these mutations in patients with anti-MAG neuropathies.
This is a retrospective observational study in patients with anti-MAG neuropathy. Mutational analysis will be performed for patients with a medullary or blood sample stored in a bio-bank during lymphocyte phenotyping. This phenotyping was carried out most often in search of a malignant haemopathy associated with the monoclonal peak. No new samples were taken from the patient (blood or spinal cord).
Immunoglobulin gene rearrangement of the clonal B cells are also assessed.
Patients with anti-MAG neuropathy followed in the Internal Medicine Ward of the Rennes University Hospital
Exclusion criterion
Mutational analysis of clonal B cells
Diagnostic Test: Mutational analysis of clonal B cells
Mutational analysis based on medullary or blood samples stored in a bio-bank during routine lymphocyte phenotyping. Mutations affecting MYD88 (MYD88 L265P mutation), CXCR4 (Whim-like CXCR4 mutation) loci are sought.
Prevalence of MYD88 L265P mutations in anti-MAG neuropathies
Mutational status of MYD88 L265P is assessed using high-throughput sequencing (HTS) and allele specific polymerase chain reaction (AS-PCR)
Time frame: At inclusion : after the patient's given consent
Prevalence of CXCR4 Whim-like mutations in anti-MAG neuropathies
Mutational status of CXCR4 is assessed using HTS and AS-PCR
Time frame: At inclusion : after the patient's given consent
Immunoglobulin gene rearrangement
Immunoglobulin gene rearrangements are determined with a multiplex PCR
Time frame: At inclusion : after the patient's given consent
Plan to share: No
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This study is completed, as verified in Feb 2018. You cannot join it, but the record below documents what was studied.
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Peripheral Nervous System Diseases→
Rennes University Hospital