Clinical and hematological characteristics of uncommon beta-globin variants in Thailand.

Hemoglobin (Hb) E is the commonest beta-globin variant in Thailand. Other uncommon variants have been rarely reported. We performed direct DNA sequencing of the entire beta-globin gene in cases showing unidentified bands by isolectric focusing electrophoresis or high-performance liquid chromatography. Six different beta-globin mutations were found in 24: 9 Hb Hope, 6 Hb New York, 4 Hb Tak, 3 Hb D Punjab, 1 Hb Pyrgos, and 1 Hb Rambam. Hb New York was misidentified as HbA on HPLC. All Hb Tak carriers had hemoglobin over 15.0 g/dL and a Hb Tak/beta(0)-thalassemia compound heterozygote presented with symptomatic polycythemia.