Diagnostic Tests

CLINICAL ASSOCIATIONS

Mitogen’s assay for anti‐myelin associated glycoproteins (MAG) is an autoimmune diagnostic test that detects autoantibodies to MAG. Myelin-associated glycoprotein (MAG or Siglec-4) is a type 1 transmembrane glycoprotein localized in periaxonal Schwann cell and oligodendrocyte membranes. MAG is a member of the SIGLEC family of proteins and is a functional ligand of the NOGO-66 receptor. In addition to being a ligand, MAG plays a role in glial-axonal interactions and is believed to be involved in myelination during nerve regeneration and is vital for the long-term survival of the myelinated axons following myelinogenesis. In the CNS MAG is one of the main myelin-associated inhibitors of axonal regeneration after injury.

MAG autoantibodies are typically associated with autoimmune peripheral neuropathies which can involve axonal degeneration / demyelination and can be acute or chronic, . The result from this autoimmune diagnostic test should be used as an aid to diagnosis since a positive result can be seen in other autoimmune disease and/or certain infectious disease.

References:
Quarles RH (March 2007). “Myelin-associated glycoprotein (MAG): past, present and beyond”. Journal of Neurochemistry. 100 (6): 1431–48. doi:10.1111/j.1471-4159.2006.04319.x. PMID 17241126.
Barton DE, et al. (October 1987). “The myelin-associated glycoprotein gene: mapping to human chromosome 19 and mouse chromosome 7 and expression in quivering mice”. Genomics. 1 (2): 107–12. doi:10.1016/0888-7543(87)90002-4. PMID 2447011.
Bjartmar C, Yin X, Trapp BD. “Axonal pathology in myelin disorders”. Journal of Neurocytology. 28 (4–5): 383–95. doi:10.1023/a:1007010205037. PMID 10739578.
McKerracher L, et al. (October 1994). “Identification of myelin-associated glycoprotein as a major myelin-derived inhibitor of neurite growth”. Neuron. 13 (4): 805–11. doi:10.1016/0896-6273(94)90247-x. PMID 7524558.