Caused by a mutation of one or more of the four genes for α hemoglobin
Diagnosis:
Hydrops fetalis (defect in all four genes)
Patients die in utero
Hemoglobin H (defect in three genes)
Severe hypochromic microcytic anemia with chronic hemolysis, splenomegaly, jaundice, cholelithiasis
Increased reticulocyte count and sketetal changes from compensatory increase in erythropoiesis
α thalassemia trait (defect in two genes)
Low MCV, but asymptomatic
Silent carrier (defect in one gene)
No signs or symptoms
