INVESTIGATION OF MICROCYTOSIS - A COMPREHENSIVE APPROACH

Microcytosis is a highly prevalent finding during blood examination. T his study investigates the causes of microcytosis (defined as mean cor puscular volume (MCV) < 82 fl) in 466 patients referred to our laborat ory for suspected hemoglobinopathy. The following data were obtained: Hb, MCV, serum iron, transferrin, ferritin, HbA2, HbF, isoelectric foc using of the Hb, gene mapping of chromosome 16 with Xba I and Bgl II a nd hybridization with an alpha- and a zeta-probe, inflammatory status. Results show that iron deficiency remains the first cause of microcyt osis (35.2% of our patients), even in a selected population such as ou rs. Deletional alpha-thalassemia, probably the most frequent hemoglobi nopathy throughout the world, represents the second most frequent caus e of microcytosis (31.1%), followed by beta-thalassemia heterozygous s tate (18.9%). Of our patients, 1.3% had microcytosis due to the presen ce of an abnormal hemoglobin (HbC, Hb S/C, HbE). Three cases (0.6%) ha d other possible causes of microcytosis. Of the remaining 60 cases, 28 had an inflammatory state. Finally, 32 cases (6.9%) remain unexplaine d; taking into consideration the origin of these cases, their hematolo gical parameters and their family history, we postulate that these cas es are at high risk for non-deletional alpha-thalassemia.