[Analysis of Genetic Characteristics of Patients with Thalassemia in the Chengdu Region, Sichuan Province].

Objective: To analyze the gene mutation types and composition characteristics of patients with thalassemia in Chengdu Region, Sichuan Province.

Methods: 6 649 suspected thalassemia patients with positive screening results who visited Chengdu Women's and Children's Center Hospital from January 2017 to December 2020 were selected as the study subjects. Among them, there were 2 273 males and 4 376 females. The frequency and distribution of α and β genotypes of thalassemia in this cohort was analyzed by Luminex liquid-phase microarray method.

Results: Among the 6 649 samples, 3 787 were genetically diagnosed as thalassemia, with a total positive rate of 56.96%; in which, 2 063 (31.03%) cases were β-thalassemia, 1 629 (24.50%) cases were α-thalassemia, and 95 (1.43%) cases were α combined with β thalassemia. The types of β-thalassemia gene mutation were mainly CD17/N (36.45%, 752/2 063), CD41-42/N (25.30%, 522/2 063), and IVS-II-654/N (24.72%, 510/2 063); and 2 037 cases of simple heterozygous mutations were identified, accounting for 98.74% of β-thalassemia patients. The types of α-thalassemia gene mutation were mainly -- ^SEA/αα (79.01%, 1 287/1 629), -α^3.7/αα (10.62%, 173/1 629), -α^3.7/-- ^SEA (2.95%, 48/1 629), and -α^4.2/αα (2.15%, 35/1 629). The α combined with β thalassemia was dominated by -α^3.7/αα; CD17/N and -α^3.7/αα; IVS-II-654/N, both accounting for 14.74% (14/95) of patients with α combined with β thalassemia.

Conclusion: In Chengdu region, Sichuan province, β thalassemia is more common than α thalassemia, the main type of β thalassemia mutation is CD17/N, and the main type of α thalassemia mutation is -- ^SEA/αα, with regional characteristics.