Hemoglobin γ Antibody #14818

Hemoglobin (Hb, Hbg) is a heme-containing transport protein found primarily in the red blood cells of humans and most other vertebrates. The primary function of hemoglobin is to transport oxygen from the external environment to body tissues. Hemoglobin also facilitates metabolic waste removal by assisting in the transport of carbon dioxide from tissues back to the respiratory organs (1). Mature hemoglobin is a tetrameric protein complex, with each subunit containing an oxygen-binding heme group (2). Multiple isoforms of hemoglobin exist, which vary in relative abundance depending on developmental stage. Adult hemoglobin (HbA) is composed of two α subunits and two β subunits and is the predominant hemoglobin found in red blood cells of children and adults. Fetal hemoglobin (HbF) contains two α subunits and two γ subunits and is the predominant isoform found during fetal and early postnatal development (2,3). Mutations that alter the structure or abundance of specific globin subunits can result in pathological conditions known as hemoglobinopathies (4). One such disorder is sickle cell disease, which is characterized by structural abnormalities that limit the oxygen carrying capacity of red blood cells. By contrast, thalassemia disorders are characterized by deficiencies in the abundance of specific hemoglobin subunits (4). Clinical treatments that are designed to alter the expression of specific hemoglobin subunits can be used to treat hemoglobinopathies (5).

A pair of genes within the human beta-globin gene cluster (HBG1, HBG2) encodes the two hemoglobin γ isoforms found in fetal hemoglobin. Mutations in both HBG1 and HBG2 promoter regions are associated with cases of hereditary persistence of fetal hemoglobin (6). Missense mutations in HBG2 can result in transient neonatal cyanosis, a disorder characterized by low oxygen saturation levels and skin discoloration that typically resolves at 5-6 months of age (7).