Analysis of β-thalassemia gene testing results in western region of Guangxi Zhuang Autonomous Region / 中华地方病学杂志

ABSTRACT

Objective:To analyze the positive detection rate, main genotypes of β-thalassemia in western region of Guangxi Zhuang Autonomous Region (referred to as Guangxi).Methods:Retrospective analysis of 26 189 individuals who underwent gene testing for thalassemia at the Affiliated Hospital of Youjiang Medical University for Nationalities from January 2013 to December 2019. Using the crossing breakpoint PCR (Gap-PCR) and reverse dot blot (RDB) techniques to detect Chinese common type of 7 kinds of α-thalassemia and 17 kinds of β-thalassemia genotypes, high-throughput sequencing(Sanger) was performed for suspected rare β-thalassemia. Gap-PCR was used for suspected deletion β-thalassemia types.Results:β-thalassemia was diagnosed in 4 495 (17.16%) of 26 189 samples. A total of 6 177 alleles of 20 types of β-thalassemia were detected, mainly CD17 (2 712 cases, 43.90%) and CD41-42 (2 240 cases, 36.26%), including 7 rare alleles: Gγ +( Aγδβ) 0, SEA-HPFH, Hb New York, Hb G-Taipei, Hb Hezhou, Hb G-Coushatta and IVS-Ⅱ-81. There were 3 903 case (86.83%) heterozygous, 273 case (6.07%) double heterozygous, and 319 case (7.10%) homozygous among 4 495 β-thalassaemia subjects. A total of 48 genotypes were detected. The two most common genotypes were CD17/β N (1 890 cases, 42.05%) and CD41-42/β N (1 212 cases, 26.96%), accounted for 69.01% (3 102/4 495). Seven rare genotypes were detected: Gγ +( Aγδβ) 0/β N in 3 cases, Hb New York/β N in 3 cases, Hb G-Taipei/β N in 2 cases, SEA-HPFH/β N, Hb Hezhou/β N, Hb G-Coushatta/β N and IVS-Ⅱ-81/β N in 1 case each. A total of 1 041 cases (3.97%, 1 041/26 189) of 116 types of αβ-thalassemia were detected, mainly -- SEA/αα composite CD17/β N (144 cases, 13.83%), followed by -α 3.7/αα composite CD17/β N (112 cases, 10.76%). Conclusions:Western region of Guangxi is a high prevalence area of β-thalassemia, CD17/β N and CD41-42/β N are the main genotypes. The variation spectrum of β-thalassemia is complex and diverse, with rich genotype.