Rare hemoglobin variants: Hb G-Szuhu (HBB: c.243C>G), Hb G-Coushatta (HBB: c.68A>C) and Hb Mizuho (HBB:c.206T>C) in Sri Lankan families

Abstract

In this short communication, we describe the clinical presentation of unusual hemoglobin (Hb), variants in three Sri Lankan cases under study for β-thalassemia intermedia (β-TI). We believe this is the first report on their occurrence in Sri Lanka as well as from the Indian subcontinent. During a molecular study performed on β-TI patients, we identified three unusual Hb variants as Hb G-Szuhu (HBB: c.243C>G), Hb G-Coushatta (HBB: c.68A>C) and Hb Mizuho (HBB: c.206T>C) in three unrelated families. Hb G-Szuhu and Hb G-Coushatta were found in combination with the common β-thalassemia (β-thal) mutation, IVS-I-5 (G>C). Both probands had mild anemia with greatly reduced red cell indices and had non palpable livers and spleens, however, by ultrasound, both were observed to be enlarged. The final Hb variant, Hb Mizuho, was identified as a heterozygous mutation found in both proband and his mother. Both family members had severe anemia and were regularly transfused and had increased red cell parameters.