Hemoglobin Pakse: presence on red blood cell membrane and detection by polymerase chain reaction-single-strand conformational polymorphism.
Nondeletional gene mutations giving rise to alpha-thalassemia can be found at polymorphic frequency in Southeast Asia. Although the most common is hemoglobin Constant Spring (Hb CS), caused by a termination codon mutation (UAA --> CAA, Gln) in the alpha2-globin gene and resulting in reduced synthesis of the elongated alpha-globin variant, Hb Pakse (UAA --> UAU, Tyr) also has been observed at a significant prevalence. Western blot analysis of ghost membrane proteins separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis from an individual with alpha-thal 1/Hb Pakse revealed the existence of a higher molecular weight globin of 18 kd consistent with an alpha(Pakse)-globin chain. The presence of alpha(Pakse)-globin on membranes of Hb Pakse-containing red blood cells affords an explanation for the severity of anemia observed in such patients. However, because the 2 Hb variants cannot be distinguished by current biochemical techniques, we developed a convenient single-tube polymerase chain reaction-single-strand conformational polymorphism (PCR-SSCP) protocol for the simultaneous diagnosis of Hb CS and Hb Pakse by amplifying a short fragment covering the termination codon of the alpha2-globin gene. This PCR-SSCP method required no internal control coamplification or use of restriction enzymes and has the potential of identifying all the other possible termination codon mutations in a single reaction with only 1 pair of primers.
Department of Biochemistry, Faculty of Science, Mahidol University, Bangkok, Thailand.
Chairat
C
Turbpaiboon
Atchasai
A
Siritantikorn
Wanna
W
Thongnoppakhun
Duangkamon
D
Bunditworapoom
Chanin
C
Limwongse
Pa-thai
PT
Yenchitsomanus
Noppadol
N
Siritanaratkul
Prapon
P
Wilairat
D003062:Codon / Q000235:genetics; D004910:Erythrocyte Membrane / Q000737:chemistry; D006580:Genetic Carrier Screening; D006455:Hemoglobins, Abnormal / Q000235:genetics*; D006801:Humans; D016133:Polymerase Chain Reaction / Q000379:methods; D018807:Polymorphism, Single-Stranded Conformational
D003062:Codon; D006455:Hemoglobins, Abnormal; C099132:hemoglobin Pakse