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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