Hb Lake Tapawingo [α46(CE4)Phe→Ser; HBA2:c.140T>C]: A New Unstable α Chain Hemoglobin Variant Associated with Low Systemic Arterial Saturation

Abstract

A new unstable alpha globin variant was detected in a child with hypoxemia and anemia. The child’s mother was found to carry the same mutation. The hemoglobin variant co-eluted with Hb A2 by cation-exchange high performance liquid chromatography (CE-HPLC) and appeared cathodal to Hb A and anodal to Hb F by isoelectric focusing. It represented less than 20% of the total hemoglobin and was unstable by isopropanol testing. Gene sequencing identified a missense mutation in the α2 gene [HBA2:c.140T>C]. Oxygen dissociation and P50 test results were normal.