Comparison of gene mutation spectrum of thalassemia in different regions of China and Southeast Asia

BACKGROUND: Thalassemia is a common genetic disorder. High prevalence of thalassemia is found in South China, Southeast Asia, India, the Middle East, and the Mediterranean regions. Thalassemia was thought to exist only in southern China, but an increasing number of cases from northern China have been recently reported.

METHODS: During 2012 to 2017, suspected thalassemia people were detected for common α- and β-thalassemia mutations by gap-Polymerase Chain Reaction (PCR) and reverse dot blot (RDB) analysis in Peking Union Medical College Hospital. One thousand and fifty-nine people with thalassemia mutations were analyzed retrospectively. We picked mutated individuals who originally came from northern areas, and conducted telephone follow-up survey in order to collect their ancestral information. Besides, we used "thalassemia", "mutation", and "Southeast Asian countries" as keywords to search the relevant studies in PubMed and Embase databases.

RESULTS: All carriers included in our study were resided in northern China. Among them, 17.3% were native northerners and 82.7% were immigrants from southern China. Although substantial difference was found in α- and β-thalassemia ratio and detailed spectrum of α- and β-globin mutation spectrum between our data and data obtained from a previous meta-analysis literature focused on southern China, the most common gene mutations were the same. Similar β-thalassemia mutation spectrum was found among Thai, Malaysian Chinese, and Guangdong people, however, no other similarities in gene profile were found between Chinese and other ethnic groups in Southeast Asia.

CONCLUSION: Chinese people in different areas had similar gene mutation, whereas they had significantly different mutation spectrums from other ethnic groups in Southeast Asia.