HBB and anemia (phenotype): Aside from dietary factors, anemia can be caused by genetic and epigenetic factors, and it has been classified into a few common types, which include sickle cell anemia and beta-thalassemia, which are caused by alterations in the HBB gene; and glucose-6-phosphate dehydrogenase deficiency (G6PD), which is caused by a polymorphic X chromosome [13–15].