Alpha-Globin Locus Deletion Homozygous Deletion of HBA1 SCDO (Jade Hotchkiss) Trans Deletion of HBA1 None Request inclusion into relevant ontology Deletion of both HBA1 genes, which results in an alpha-thal-2 (alpha-/alpha-) form of alpha thalassemia trait. With this deletion there is nearly normal production of red blood cells, but there may be a mild anemia.