HbQ-India associated with microcytosis: An uncommon hemoglobin variant associated with a common hematologic condition.

Abstract

HbQ-India is a rare alpha chain variant that usually presents in the heterozygous state. Normally, HbQ-India is clinically silent. It becomes symptomatic when present in association with other conditions. We report a case of HbQ-India with concomitant presence of iron deficiency anemia. A 16-year-old female presented with weakness and pallor intermittently for six years. Complete blood count showed severe microcytic hypochromic anemia. Hemoglobin electrophoresis showed a prominent band in the S,D,G region. Tests for sickling were negative. High performance liquid chromatography (HPLC) showed a peak in the unknown window (4.70-4.90 min) suggestive of HbQ-India. Serum iron profile was suggestive of iron deficiency anemia. Based on the above findings, a diagnosis of coexistent HbQ-India-iron deficiency anemia was made. A family study revealed the father as having moderate anemia with similar findings while the mother was normal. Abnormal hemoglobin in the patient was confirmed by molecular diagnosis. HbQ variants are the alpha globin chain variants due to structural mutations (α64 Asp→His) inherited in autosomal dominant fashion. Three molecular variant types have been documented, namely HbQ-India, HbQ-Thailand and HbQ-Iran. Normally, HbQ is clinically silent. Therefore, careful screening of the samples using routine techniques like Hb electrophoresis and HPLC are needed for identification of such abnormal hemoglobin variants like HbQ-India.