PPIB and thalassemia: For example, CD17 was the most frequent β-thalassemia mutation with an allele frequency of 40.22% in this Baise region in Guangxi [6], where CD41–42 was the most common mutation in Guangdong [18, 19], and the first two mutations in Hainan Province were CD41–42, and IVS-II-654 [7], the top three mutations in Yunnan province were CD26, CD17 and CD41–42 [20].