Detection of three common, deletional α-thalassemia determinants in Southern China by a single-tube multiplex polymerase chain reaction method

alpha-Thalassemia (thal) is one of the most common inherited disorders in the world and in Southern China. Three large deletions of the alpha-globin gene, namely the -alpha(3.7) and -alpha(4.2) (single gene deletions), and --(SEA) (Southeast Asian double gene deletion), are the main alpha-thal abnormalities in Southern China. We have developed a reliable, single-tube multiplex polymerase chain reaction (m-PCR) assay for these three most frequently observed determinants in Southern China. By using this assay, we detected 40 alpha-thal patients from Guangdong, Guangxi Province, and analyzed 116 blood samples from the Li ethnic group of Hainan Province. To our surprise, the combined incidence of -alpha(3.7) and -alpha(4.2) was found to be as high as 38.0% among the Li people, and the -alpha(4.2) genotype is more frequent than -alpha(3.7) in the Li people. No SEA deletions were found in the Li samples.