We introduced in our �Neurology Test Center� a panel to include most cases of peripheral neuropathies due to autoantibodies. The following summary includes the most common peripheral neuropathies diseases that we examine in our lab
Anti-GM1 antibody causes conduction block, mild axonal degeneration and IgM deposits at nodes of Ranvier
IgM Anti GM1: associated with Multifocal Motor Neuropathy (MMN) and distal motor neuron syndrome. Electrophysiology shows motor only conduction block with axonal loss. EMG shows no paraspinous denervation.. Monoclonal M-protein presents in 20% of cases
IgG anti GM1: associated with Acute Motor Axonal Neuropathy (commonly) or Chronic Distal lower motor neuron syndrome – rare
Positive tests for IgM GM1 usually indicates treatable MMN from other immune neuropathies. Best treatment is achieved by HIG, B-cell immunosuppression, plasma exchange, cyclophosphamide , with possible Rituxan
:Anti-GM2
IgM Anti-GM2: Associated with Guillian Barre syndrome variants, Motor neuropathy and sensory demyelinating neuropathy
IgM GM2: is associated with acute neuropathy (GBS-variant), or Chronic Demyelinating Polyneuropathy
IgG GM2: associated with acute motor neuropathy with distal predominant weakness and sparing of the cranial nerves. Or chronic neuropathy with chronic axonal motor neuropathy
Anti-GQ1b: IgG-GQ1b antibodies work on binding peripheral nerves and brain stem structures and may produce presynaptic blockade of neurotransmitter release from motor nerve terminals. This disease is considered as a variant of Guillain Barrei syndrome (with ataxic features).. Monoclonal gammopathy is common in this disorder. It is associated with prodromal Campylobacter jejuni infection
Anti-GD1b: IgM-GD1b antibody cross react with antigens on red blood cells and may cause cold agglutinin.. Both IgG and IgM present in peripheral nerves on the surface of sensory neurons in the dorsal root ganglion and paranodal myelin. It is associated with sensory neuropathy +/- cranial nerve syndrome. Ataxia may develop in these patients
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Cont/ Circular 49-Peripheral Neuropathy
:Anti-GD1a
IgM Anti-GD1a: associated with demyelinating motor neuropathy; and demyelinating sensory-motor neuropathy
IgG Anti-GD1a: anti GD1a associated with Guillain Barre-like syndromes, predominantly motor and axonal involvement, usually spares the cranial nerves
The disease is immune mediated with possible response with plasma exchanges or IV Immunoblobulins. Spontaneous recovery occurs in most of the people. The disease is associated with prodromal Campylobacter jejuni infection
Anti-Hu of IgG type: antibody located in neuronal nuclei. It is usually pure sensory syndrome (ganglionaopthy) with limbic encephalitis , cerebellar disorders, GI dysfunction
Anti-Yo antibodies of IgG type: antibody against Golgi apparatus in Purkinje cell cytoplasm. Associated with cerebellar syndrome in Paraneoplastic syndrome
Anti-MAG: antibodies
Anti-MAG antibodies binds to compact peripheral nervous system myelin, Schwann cell cytoplasm and occasionally axons, which causes the demyelinating process and usually it is of IgM type. The disease caused is Chronic demyelinating sensory-motor polyneuropathy, signs of sensory loss, Gait ataxia, tremor, mild distal weakness. Treated with plasma exchanges and IV cyclophosphomide and Rituxan. Associated with serum M-protein
Anti-GAD antibodies: (Glutamic Acid Decarboxylase). GAD receptors present in the cerebellum and other neurological organs associated with Stiff man syndrome (a syndrome of diffuse hypertonia of the muscles due to loss of inhibitory spinal interneurons), Amyotrophic lateral sclerosis and Cerebellar degeneration
Again, we strongly recommend to request Peripheral Neuropathy Panel for evaluation of cases with neuronal disorders
To remind you, in our lab we also do muscle biopsy (with all the muscle enzymes), nerve biopsy (with all the stains and electron microscopy), chromosomal studies, and many other neurological tests
We, in the First Medical Laboratory, are determined to bring the best of laboratory medicine in clinical practice to Jordan
Please do not hesitate to contact me for further inquiry
Dr. Hussam Abu-Farsakh
American boards of Anatomic, Clinical Pathology and Cytopathology
Circular: is a periodic circular that distributed to clinician informing them about new and important tests available at First Medical Laboratory. All information listed are supported by recent literature
:Summary
MMN GM1 80
GBS GM1, GD1a 20-30
Miller Fisher GQ1b 95
Anti-MAG Anti-MAG 50-65
Paraneoplastic Anti-Hu
Sensory Neuropathy Sulphatide