[Genetic Differences of Thalassemia Gene Among Ethnic Groups in Hechi, Guangxi].

Objective: To retrospectively analyze the genetic differences of thalassemia gene mutations among ethnic groups in Hechi, Guangxi.

Methods: A total of 15 595 whole blood samples of residents of Hechi from January 1, 2020 to June 30, 2023 were screened for thalassemia, and the Gap-PCR method and RDB-PCR method were used to perform genetic testing on the positive samples. Gene sequencing was performed on the samples with positive screening results but negative genotyping results.

Results: Among the 15 595 samples, 10 501 cases were screened positively, and 8 506 cases were thalassemia gene carriers among the positive samples, with a positive coincidence rate of 81.00%. Among them, there were 5 374 cases of α-thalassemia, 2 531 cases of β-thalassemia, and 601 cases of α+β compound thalassemia. A total of 13 mutant types were detected in α-thalassemia, including --^SEA (48.57%), -α ^3.7 (31.31%), α ^CS (8.57%) and -α ^4.2 (8.07%). A total of 17 mutant types were detected in β-thalassemia, mainly CD17 (48.27%) and CD41-42 (41.24%). The thalassemia gene carriers were mainly from the Zhuang (6 106 cases), Han (969 cases), Yao (793 cases), Mulam (275 cases), and Maonan (228 cases) ethnic groups. The comparison of constituent ratios within the above five ethnic groups demonstrated that there were differences in the proportions of -- ^SEA, -α ^3.7, α ^CS , and -α ^4.2 among the Zhuang, Han, and Yao ethnic groups (P < 0.005). The proportion of α ^CS in the Mulam ethnic group was not significantly different from -α ^3.7 and -α ^4.2. The proportions of -- ^SEA, -α^3.7, and α ^CS in the Maonan ethnic group were not significantly different. There were no significant differences in the proportion of CD17 and CD41-42 among the Han, Yao, Mulam and Maonan ethnic groups. The proportion of --^SEA was the highest in the Mulam ethnic group (56.68%), which was statistically different from 35.92% in the Maonan ethnic group. The proportion of -α ^3.7 was the highest in the Zhuang ethnic group (33.25%), and the difference was statistically significant compared to the Mulam ethnic group which had the lowest proportion (18.72%). The proportion of α ^CS was the highest in the Maonan ethnic group (27.46%), and the differences were statistically significant compared with other ethnic groups. The proportions of CD17 in the Zhuang and Maonan ethnic groups (50.79%, 55.68%) were higher than those in the Han (39.12%), Yao (39.63%) and Mulam (30.00%), and the differences were statistically significant. There was no significant difference in the proportion of CD41-42 among the above five ethnic groups.

Conclusions: The mutation type and distribution differences of genes causing thalassemia among main ethnic groups in the minority inhabited areas of Hechi, Guangxi, show the characteristics of ethnic differentiation. The result is helpful to develop a special prevention and control plan for thalassemia in line with the population distribution characteristics, and provide reference for revealing the genetic background and geographical distribution of thalassemia in this area.