Figure 1.
Comparison of the human and zebrafish diseases associated with mutations in ALAS-2. The red blood cells in the peripheral blood are normally round and uniform. In human congenital sideroblastic anemia, cells have abnormal shapes and are hypochromic (due to a low level of hemoglobin). Red cell precursors, such as reticulocytes, are larger (arrowheads). The increase in reticulocytes indicates a response of the marrow to the anemia. A similar hypochromia and increase in precursors is evident in the peripheral blood smear of sauhomozygous mutants (arrows).
