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