What typically causes Alpha-Thalassemia?

Alpha-Thalassemia is primarily caused by gene deletions, which result in the reduced production of alpha-globin chains necessary for hemoglobin formation. The condition manifests when one or more of the alpha-globin genes located on chromosome 16 are deleted. Typically, there are four alpha-globin genes, and the severity of alpha-thalassemia correlates with the number of genes affected.

For instance, deletion of one or two genes can lead to mild forms of the disease, while deletion of three or four genes can result in severe conditions like Hemoglobin H disease or alpha-thalassemia major. This genetic basis highlights how the absence of functional alpha-globin chains leads to unbalanced hemoglobin synthesis, resulting in ineffective erythropoiesis, microcytic anemia, and various complications associated with thalassemia.

Other options, such as gene mutations or environmental factors, do play roles in various other genetic disorders or diseases but are not the primary cause of alpha-thalassemia. Infectious agents are also not relevant in the context of causing this particular hematological disorder. Gene deletions, therefore, are the hallmark of alpha-thalassemia, making this the correct answer.