hemoglobinopathy /hē′mōglō′binop″əthē, hem′-/ [Gk, haima + L, globus, ball; Gk, pathos, disease] , a group of inherited disorders characterized by structural variations of the hemoglobin molecule. An abnormality may occur in the heterozygous or the homozygous form. The alteration appears as the substitution of one or more amino acids in the globin portion of the molecule at selected positions in the two alpha or two beta polypeptide chains. Although more than 100 variants have been described, only hemoglobins S and C are commonly seen. In the heterozygous form the normal adult pigment, hemoglobin A, and the variant both appear in the red cell. Little or no clinical manifestation of disease may be present. In the homozygous form only the variant hemoglobin is present, and the characteristic symptoms of that hemoglobinopathy appear. Mixed heterozygous forms are also known to occur. The normal hemoglobin A may be absent, and two or three hemoglobin variants may be present. Also spelled haemoglobinopathy. Compare thalassemia. Kinds include hemoglobin C disease, hemoglobin SC (Hb SC) disease, sickle cell anemia. See also hemoglobin, hemoglobin A, sickle cell thalassemia, sickle cell trait.
