Gene Mutation Spectrum of Thalassemia Among Children in Yunnan Province.

Background: Thalassemia is an autosomal genetic disorder, found throughout the world. It is still not treatable and create socio economic problems. In this study, we investigated the prevalence and spectrum features of thalassemia in Yunnan Province, the southwestern area of China. During 2014-2018, a total of 3,539 suspected thalassemia children were detected with alpha- and beta-thalassemia mutations by gap-Polymerase Chain Reaction (PCR) and reverse dot blot (RDB) analysis in Kunming Children's Hospital. Results: Of these patients, 1,130 were diagnosed thalassemia gene carriers with a carrying rate of 31.92%. Among them, alpha-thalassemia was 43.63%, beta-thalassemia was 53.98%, cases with both alpha- and beta- thalassemia was 2.39%. In alpha-thalassemia patients, the most common mutations was -(SEA)/alpha alpha (52.13%), followed by -alpha(3.7)/alpha alpha (27.79%), hemoglobin H disease (18.46%), and -alpha(4.2)/alpha alpha (1.62%). Fifteen gene mutations and 30 genotypes were identified in beta-thalassemia patients, with the five most common mutations CD17 (A>T) (29.51%), CD41-42 (-TTCT) (27.87%), IVS-II-654 (C>T) (14.92%), CD26 (G>A) (6.89%), and CD26/CD27 (2.62%) accounting for 81.81% of the beta-globin gene mutations. Furthermore, we founded two rare mutations CD34 (TGG -> TAG) and Int in Chinese populations. Conclusions: Our results suggested that the prevalence and gene mutation spectrum of thalassemia display obviously heterogeneity among children in Yunnan Province. The findings provide the valuable information for premarital and pre-pregnancy screening, prenatal diagnostic services, and designing appropriate prevention programs to control thalassemia for future in this area.