HbQ-India in a Sindhi family: an uncommon hemoglobin variant.

Hemoglobin Q-India is a very rare alpha-chain structural variant caused by the mutation AAG-->GAG (Asp-->His) in the position of codon 64 of the alpha1 gene. Usually it presents in the heterozygous form with electrophoretic mobility in the position of hemoglobin S (HbS) at alkaline pH along with the double bands of HbA2. High-performance liquid chromatography (HPLC) retention time of 4.76 minutes for this abnormal Hb variant identifies it to be HbQ-India. Only isolated case reports exist in literature to describe this rare entity. On cellulose acetate electrophoresis at alkaline pH, the HbQ band can easily be misinterpreted as HbS or HbD if careful screening of the patient for sickle cell with solubility test or sickling test is not done and the abnormal HbA2 band is overlooked. We report a case and emphasize the importance of careful screening with electrophoresis and HPLC in the diagnosis of this rare condition