| ![](skn/spacer.gif) | Hemoglobin is produced by genes that control the expression of the hemoglobin protein. Defects in these genes can produce abnormal hemoglobins and anemia, which are conditions termed "hemoglobinopathies". |
| ![](res/ac3/img/spacer.gif) | | ![](skn/spacer.gif) | There are hundreds of hemoglobin variants that involve genes both from the alpha and beta gene clusters. |
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