Hb Paksé [(α2) CODON 142 (TA A→TA T OR Term→Tyr)] IN THAI PATIENTS WITH EABart's DISEASE AND Hb H DISEASE

Abstract

Hb Paksé is caused by an α2-globin gene termination codon mutation, TA A→TA T or Term→Tyr, initially described in a Laotian family. We now report for the first time that the same mutation has been found in 14 Thai patients, seven with EABart's disease, four with Hb H disease, and three with α-thalassemia trait who were initially diagnosed as having Hb Constant Spring (Hb CS; α2-globin gene termination codon mutation T AA→C AA or Term→Gln). Co-inheritance of this mutation with α-thalassemia-1 (SEA type) leads to Hb H disease (hereafter designated as Hb H-Paksé disease) and to a complex thalassemia syndrome, namely EABart's-Paksé disease. Hematological data of these patients were compared with those of classical Hb H-CS and the EABart's patients. To facilitate epidemiological and diagnostic screening of Hb Paksé, a simple assay procedure based on allele specific polymerase chain reaction (PCR) amplifications was developed and validated. Using this allele specific PCR as a screening method, five additional individuals with Hb Paksé were found among 71 Thai subjects previously thought to have Hb CS.