OBJECTIVETo investigate the gene mutation frequencies and patterns of β-thalassemia (β-thal) in the minority populations of Guizhou province.

METHODSThree thousand and five hundred couples in the reproductive age were screened by using automatic hemocyte analyzer and hemoglobin autoanalyzer-variant. The diagnostic criteria for β-thal were: the mean corpuscular volume (MCV) was ≤ 82 fl, and the HbA(2) level was ≥ 3.5%. A total of 194 positive samples were detected and further identified by PCR-reverse dot blot (PCR-RDB) assay for 18 common β -thal mutations in Chinese population. Those subjects with positive phenotypes but without the 18 common β-thal mutations were subjected to DNA sequence analysis of the β-globin gene.

RESULTSOne hundred and eighty-nine samples with gene mutations were observed from the 3500 samples, with the incidence of β-thal being 5.4%. A total of 10 different β-thal mutations were identified from the 189 diagnosed samples. The five most common mutations were as the following: CD17 (43.9%), CD41-42 (38.6%), IVS-II-654(10.1%), -28 (2.6%) and CD71-72 (1.6%). In addition, a novel β-globin gene mutation (-CD53) allele was detected. One rare mutation of IntM was observed.

CONCLUSIONThe minority population in Guizhou province is of high risk of β-thal. It is recommended that more attention should be paid to detect the carriers of β-thal in the population in reproductive age by hematologic screening and common gene diagnosis in the area with high risk of β-thal.