Alpha-thalassemia
Four genes are involved in making the alpha hemoglobin chain. You get two from each of your parents. If you inherit:
One mutated gene, you'll have no signs or symptoms of thalassemia. But, you are a carrier of the disease and can pass it on to your children.
Two mutated genes, your thalassemia signs and symptoms will be mild. This condition may be called alpha-thalassemia minor, or you may be told you have an alpha-thalassemia trait.
Three mutated genes, your signs and symptoms will be moderate to severe. This condition is also called hemoglobin H disease.
Four mutated genes, the condition is called alpha-thalassemia major or hydrops fetalis. It usually causes a fetus to die before delivery or a newborn to die shortly after birth.