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Q: I have been told that I have monoclonal gammopathy of unknown significance. It has been diagnosed as benign. If you could give me some more information concerning this desease, I would really appreciate it. Thank you in advance.

Dr. Keti:

Monoclonal Gammopathy is an associated laboratory abnormality seen in most patients with paraproteinemia.

A group of related diseases characterized by an unbalanced or disproportionate proliferation of immunoglobulin-producing cells, usually from a single clone.
These cells frequently secrete a structurally homogeneous immunoglobulin (M-component) and/or an abnormal immunoglobulin. The paraproteinemia most commonly seen is of a monoclonal lgG gammopathy. Most monoclonal gammopathies are of benign type.

Benign Monoclonal Gammopathies
Conditions characterized by the presence of a monoclonal serum (or urine) protein without clinical manifestations of plasma cell dyscrasia (abnormality of the cells).
However, Monoclonal Gammopathy is associated with many other conditions as listed below:

Coincidental Presense Of Monoclonal Gammopathies
Monoclonal gammopathies are also nonspecifically increased in chronic inflammatory or infectious diseases and in old age. They can also occur in chronic inflammatory demyelinating polyneuropathy.

Schnitzler Syndrome
An extremely rare condition manifested as monoclonal IgM dysproteinemia without features of lymphoproliferative disease, but with chronic urticaria (eruption of red pimples and wheals), fever of unknown origin, disabling bone pain, hyperostosis(excessive or abnormal thickening or growth of bone tissue), and increased erythrocyte(red cells) sedimentation rate.

Monoclonal Gammopathies Associated With Neuropathies
IgM monoclonal gammopathies are associated with many neuropathies either of hereditary or immune-mediated or lymphoproliferative disease. The distinction is important because immune-mediated neuropathies are responsive to drug therapy, whereas hereditary neuropathies are not, and hereditary neuropathies can be passed on to future generations. Some families exhibit a predisposition to the development of IgM monoclonal gammopathies or Waldenström macroglobulinemia and since up to 50% of patients with IgM monoclonal gammopathies can develop neuropathy, there is a finite probability that both conditions can occur in more than one family member.

The presence of a monoclonal gammopathy in a patient with neuropathy may alert the physician to the possible occurrence of an associated autoimmune or lymphoproliferative disease.

Monoclonal Gammopathies Can Be Associated With Myeloma
Most monoclonal gammopathies are benign (nonmalignant), but those of the IgG type can be associated with myeloma, the plasma cell dyscrasia with polyneuropathy, organomegaly(enlarged organs) and enlarged lymph nodes, endocrinopathy (enlarged and malfunctioning glands), monoclonal protein, skin changes syndrome or Amyloidosis.
The IgM monoclonal gammopathies are sometimes associated with:
Waldenström macroglobulinemia
chronic lymphocytic leukemia or lymphoma, cryoglobulinemia, or autoantibody activity to peripheral nerves.

Monoclonal Gammopathies And Autoimmune Disorders
The two most important clinical types of antiphospholipid-protein antibodies are traditionally called lupus anticoagulant (LA) and anticardiolipin (aCL) antibodies. These antibodies are associated in some patients, but not in others with clinical illness of varying severity. Individual patients may manifest arterial or venous thrombosis, thrombocytopenia (decreased number of platelets) as in Lupus and platelet dysfunction, recurrent pregnancy loss, neurologic and skin abnormalities.

Tests that are in use to differentiate the monoclonal gammopathies:
Electrophysiological , serological and radiologic tests studies can help distinguish between the different types and DNA testing can identify or rule out most but not all hereditary demyelinating neuropathies. However, many patients present atypically and there is significant overlap of abnormalities between the different groups.

References and Additional Informative Sites are listed below:

    Norman Latov, MD, PhD
    A clinical analysis of 798 cases

    National Library of Medicine

    Antiphospholipid Antibody Syndrome: Lupus Anticoagulants and Anticardiolipin Antibodies, by Judith D. Laval, MD

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