Autoimmune demyelinating neuropathies include several progressive conditions — among them chronic inflammatory demyelinating polyneuropathy (CIDP), Guillain-Barre syndrome (GBS), chronic immune sensory polyradiculopathy (CISP), and distal acquired demyelinating sensory (DADS) neuropathy — that share overlapping motor and/or sensory features with other peripheral neuropathies.
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Frequently misdiagnosed, CIDP in most cases is highly responsive to first-line immunotherapy treatments, such as intravenous immunoglobin (IVIG). However, a subset of individuals with specific paranodal antibodies do not respond as well to these therapies. The presence of neurofascin 155 (NF155) IgG4 and contactin-1 (CNTN1) IgG indicates a unique disease etiology with antibodies targeting the paranode. These patients have relatively poor treatment response to IVIG. We’ve developed and validated a unique assay combination available exclusively at Mayo Clinic Laboratories.
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Divyanshu (Div) Dubey, M.B.B.S., describes Mayo Clinic Laboratories' new diagnostic test for CIDP, or chronic inflammatory demyelinating polyneuropathy. The new test detects two antibodies — NF155 and CNTN1 — to enhance diagnosis and guide treatment decisions. Often misdiagnosed, CIDP is treatable if detected early.
Sophisticated laboratory testing solved a medical riddle and finally got Jori Pearson back on his feet, doing what he loves.
The presence of myelin associated glycoprotein (MAG) antibodies is often linked to a rare demyelinating neuropathy with poor treatment response known as DADS neuropathy. In some cases, reaching correct diagnosis through clinical and electrophysiological evaluation alone can be difficult due to overlapping features, or when patient evaluation occurs later in the disease course. Incorporating MAG antibody testing into the diagnostic workup can help identify the correct diagnosis and exclude patients with treatable immune-mediated neuropathies.
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John Mills, Ph.D., explains Mayo Clinic Laboratories’ approach to MAG antibody testing. The ELISA-based assay uses higher reference ranges and human MAG antigen to detect MAG antibodies, which are associated with a rare, hard-to-treat condition known as DADS neuropathy.
In patient with DADS, the body generates monoclonal immunoglobulin (IgM) antibodies that bind to and prevent MAG antibodies from properly signaling the nervous system, which causes motor and sensory issues. Despite most cases of DADS having an associated IgM M-protein, conventional testing methodologies (e.g., serum electrophoresis and immunofixation) can sometimes be negative and result in delayed diagnosis. MASS-FIX testing offers enhanced specificity and sensitivity, enabling detection of the lowest possible amount of M-proteins and providing diagnostic certainty for the rare, hard-to-treat illness.
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