One or two a gene deletions are clinically asymptomatic, although they are associated with various
degrees of microcytosis and erythrocytosis. a0-Thalassemia, a two-gene deletion (--/aa), is characterized
by a very mild anemia (within 1.0–1.5 g/dl of normal). Low MCV, mean corpuscular hemoglobin
concentration (MCHC), and mean corpuscular hemoglobin (MCH), as well as increased RBC, are also
more prominent in a0-thalassemia than in a+ genotype[24]. The microcytosis is occasionally assumed to
be the result of nutritional iron deficiency and is treated as such. This can result in unnecessary or
potentially harmful iron supplementation.