Study On Molecular Epidemiology Of The Alpha-Thalassemias In Liuzhou City, Guangxi Autonomous Region, China

Guangxi is one of the provinces of Southern China with the highest incidence of alpha-thalassemia (thal). Liuzhou is the second biggest city in Guangxi. To find out the incidence of the various alpha-thal genotypes, and their distribution in the Liuzhou area, an F820 Blood Cell Analysis System was used to measure the parameters of red blood cells. A SPIFE Rapid Auto-Electrophoresis System was used to analyze the normal and abnormal hemoglobins (Hbs). Multiplex polymerase chain reaction (mPCR) was used to detect the alpha-globin genotypes. Thirty-two (2.05%) out of 7805 young couples undergoing pre-marriage counseling, were diagnosed as having an Hb H (N) disease. The study of 1228 cord blood samples revealed 138 newborn children carrying an alpha-thal determinant with nine different genotypes, thus making the total incidence of alpha-thal 11.24%. Among 185 cases of Hb H, 119 (64.1%) were confirmed as being deletional, and 66 cases (35.7%) nondeletional types. The severity of the Hb H diseases could be classified in the following order: alpha(CS)alpha/--(SEA) (alpha(Constant) (Spring) alpha/--(Southeast Asia)); alpha(-4.2)/--(SEA;),alpha(-3.7)/--(SEA). Ten cases of alpha-thal determinants were found in combination with beta-thal. The MPCR technique can detect all kinds of combinations of the three common large deletions (--(SEA), alpha(-4.2) and alpha(-3,7)) accurately and conveniently.