Key words
Epidemiology, monoclonal gammopathy, Morocco, Monoclonal protein.
INTRODUCTION
Monoclonal gammopathies (MG) represent a group of pathologies characterized by the clonal proliferation of plasma cells that produce a paraprotein or monoclonal protein (M-protein). The generalization of the screening of the MG by serum protein electrophoresis, which represents a heterogeneous group of diseases, and especially the evolution of imaging and radiology techniques, have made possible to diagnose MG frequently and at early stages. The most important risk factors are age, gender and black race. Several studies have reported a mean age of patients at the time of diagnosis of monoclonal gammopathy of 68 years, most patients (99%) were over 40 years old at the time of diagnosis1,2. Regarding gender, monoclonal gammopathies affect men more than women. In a retrospective study, the age-adjusted incidence of monoclonal gammopathies was 10.3 and 8.6 per 100,000 in men and women, respectively 3 . Finally, for the black race, in a study found that the prevalence of monoclonal gammopathies of undetermined significance (MGUS) in men from Ghana (5.84% (95% CI, 4.27-7.40)) was significantly higher than the prevalence in white men from Olmsted in the USA (2.97%, (95% CI, 2.59-3.34))4,5 .
Monoclonal gammopathy of undetermined signification (MGUS), is defined by the production of monoclonal protein without any systemic effect. It represents the early stage of the multiple myeloma (malignant stage). MGUS accounts for 3% of MG in patients over 50 years of age6 . In general, MGUS will progress to hematologic malignancies including multiple myeloma or MM, which progresses at a rate of 1% per year 7 .
MM represents 10% of hematologic malignancies in general, the median age at diagnosis is estimated to be 70 years, and it affects more men (7 per 100,000) than women (4.5 per 100,000), blacks more than whites, thus, the highest prevalence rate is observed in African Americans, particularly in those aged 80-84 years and older 6 . Furthermore, the most frequently observed primary immunoglobulin heavy chain (IgH) translocation was t(11;14), found in 16% of patients in the absence of trisomies, and in 3% in the presence of trisomies8 . Nevertheless, the following cytogenetic abnormalities, t(4;14), t(14;16), t(14;20), del(17p), gain 1q, or p53 mutation are associated with high risk MM 8 .
To describe the epidemiological and immunochemical characteristics of monoclonal gammopathies diagnosed during a nineteen-year period in a Moroccan teaching hospital was the main objective of this study.
MATERIALS AND METHODS