Investigation of microcytosis: a comprehensive approach.
Microcytosis is a highly prevalent finding during blood examination. This study investigates the causes of microcytosis (defined as mean corpuscular volume (MCV) < 82 fl) in 466 patients referred to our laboratory for suspected hemoglobinopathy. The following data were obtained: Hb, MCV, serum iron, transferrin, ferritin, HbA2, HbF, isoelectric focusing of the Hb, gene mapping of chromosome 16 with Xba I and Bgl II and hybridization with an alpha- and a zeta-probe, inflammatory status. Results show that iron deficiency remains the first cause of microcytosis (35.2% of our patients), even in a selected population such as ours. Deletional alpha-thalassemia, probably the most frequent hemoglobinopathy throughout the world, represents the second most frequent cause of microcytosis (31.1%), followed by beta-thalassemia heterozygous state (18.9%). Of our patients, 1.3% had microcytosis due to the presence of an abnormal hemoglobin (HbC, Hb S/C, HbE). Three cases (0.6%) had other possible causes of microcytosis. Of the remaining 60 cases, 28 had an inflammatory state. Finally, 32 cases (6.9%) remain unexplained; taking into consideration the origin of these cases, their hematological parameters and their family history, we postulate that these cases are at high risk for non-deletional alpha-thalassemia.
Mach-Pascual
S
S
Division of Hematology, University Hospital, Geneva, Switzerland.
Darbellay
R
R
Pilotto
P A
PA
Beris
P
P
D002874:Chromosome Mapping; D002885:Chromosomes, Human, Pair 16; D004909:Erythrocyte Indices; D004913:Erythrocytes, Abnormal; D017353:Gene Deletion; D006445:Hemoglobin C Disease / Q000097:blood; D006446:Hemoglobin E; D006450:Hemoglobin SC Disease / Q000097:blood; D006453:Hemoglobinopathies / Q000097:blood* / Q000235:genetics; D006579:Heterozygote; D006801:Humans; D007249:Inflammation / Q000097:blood; D000090463:Iron Deficiencies; D017085:alpha-Thalassemia / Q000097:blood / Q000235:genetics; D017086:beta-Thalassemia / Q000097:blood / Q000235:genetics
D006446:Hemoglobin E