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Lin W, Zhang Q, Shen Z, Qu X, Wang Q, Wei L, Qiu Y, Yang J, Xu X, Lao J. Molecular and phenotype characterization of an elongated β-globin variant produced by HBB:C.313delA. Int J Lab Hematol 2021; 43:1620-1627. [PMID: 34271589 DOI: 10.1111/ijlh.13639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 05/25/2021] [Accepted: 06/02/2021] [Indexed: 11/27/2022]
Abstract
INTRODUCTION β-thalassemia is a severe hereditary hemolytic anemia. Due to the diversity of mutations spectrum, β-thalassemia manifests a highly heterogeneous clinical severity. We noted that a previous report characterized HBB:c.313delA, at the end of exon 2, as a β-thalassemia trait rather than dominant β-thalassemia, the classification given to similar mutations. We further explored the impact of this functional variant on globin structure through larger pedigree analysis and in vitro studies. METHODS Hematological analysis and molecular genotyping were conducted on the proband and his family members. We evaluated functional effects of the variant on β-globin gene in the proband's nucleated erythrocytes and transfected HEK-293T cells. Three-dimensional construction of protein structure was carried out in silico to demonstrate amino acid changes. RESULTS The thalassemia major proband was identified as a compound heterozygote of HBB:c.313delA and HBB:c.126_129delCTTT. Three family members with heterozygotes of HBB:c.313delA displayed microcytic hypochromic anemia. Molecular characterization demonstrated that the frameshift mutation could give rise to retro-positioning of the termination codon, resulting in an elongated β-globin chain with an extension of 10 amino acids. Clinical phenotype and functional experiments indicated that HBB:c.313delA led to β0 -thalassemia phenotype. CONCLUSION We concluded that the phenotype of HBB:c.313delA was mainly related to the stability of mutant mRNA, the degradation of mutant proteins, and production of inclusion bodies according to a systematic description of clinical phenotype and a series of molecular experiments.
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Affiliation(s)
- Wanying Lin
- Department of Medical Genetics, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China.,Guangdong Genetics Testing Engineering Research Center, Guangzhou, China.,Guangdong Provincial Key Laboratory of Single Cell Technology and Application, Guangzhou, China
| | - Qianqian Zhang
- Department of Medical Genetics, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China.,Guangdong Genetics Testing Engineering Research Center, Guangzhou, China.,Guangdong Provincial Key Laboratory of Single Cell Technology and Application, Guangzhou, China
| | - Zongrui Shen
- Department of Medical Genetics, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China.,Guangdong Genetics Testing Engineering Research Center, Guangzhou, China.,Guangdong Provincial Key Laboratory of Single Cell Technology and Application, Guangzhou, China
| | - Xiang Qu
- Department of Pediatrics, Liuzhou Worker's Hospital, Fourth Affiliated Hospital of Guangxi Medical University, Liuzhou, China
| | - Qi Wang
- Department of Pediatrics, Liuzhou Worker's Hospital, Fourth Affiliated Hospital of Guangxi Medical University, Liuzhou, China
| | - Liuyuan Wei
- Department of Pediatrics, Liuzhou Worker's Hospital, Fourth Affiliated Hospital of Guangxi Medical University, Liuzhou, China
| | - Yuhao Qiu
- Department of Pediatrics, Liuzhou Worker's Hospital, Fourth Affiliated Hospital of Guangxi Medical University, Liuzhou, China
| | - Jie Yang
- Department of Pediatrics, Liuzhou Worker's Hospital, Fourth Affiliated Hospital of Guangxi Medical University, Liuzhou, China
| | - Xiangmin Xu
- Department of Medical Genetics, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China.,Guangdong Genetics Testing Engineering Research Center, Guangzhou, China.,Guangdong Provincial Key Laboratory of Single Cell Technology and Application, Guangzhou, China
| | - Jinquan Lao
- Department of Pediatrics, Liuzhou Worker's Hospital, Fourth Affiliated Hospital of Guangxi Medical University, Liuzhou, China
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Xu ML, Qin JC, Chen BY, Yang XX, Liu HP, Yuan WX, Zhong JM, Huang LM, Zhou WJ. Characterization of a Novel 71.8 kb α 0-Thalassemia Deletion and Subsequent Summary of a Practical Procedure for Thalassemia Molecular Diagnosis. Hemoglobin 2020; 44:259-263. [PMID: 32646243 DOI: 10.1080/03630269.2020.1790385] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Thalassemia is the most common monogenic disorder around the world. Based on the principle of genotype-phenotype correlation, identification of thalassemia mutations is the essential prerequisite for clinical diagnosis and management. Because only common mutations are routinely detected, the identification of rare or undetermined mutations is a challenge for clinical laboratories. Herein, a proband presenting with inconsistent phenotype-genotype correlation after routine molecular screening was investigated by multiplex ligation-dependent probe amplification (MLPA), targeted-next generation sequencing (targeted-NGS), gap-polymerase chain reaction (gap-PCR) and Sanger sequencing. Eventually, a novel 71.8 kb deletion (- -71.8) was identified and characterized, which included HBZ (ζ), HBA2 (α2), and HBA1 (α1) genes and was causing α0-thalassemia (α0-thal). Furthermore, we summarized a practical procedure based on accumulated experience in studies and clinical practice, which can be a guide for molecular screening and clinical diagnosis of thalassemia, especially for identification of undetermined or novel mutations.
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Affiliation(s)
- Ming-Li Xu
- Department of Medical Genetics, School of Basic Medical Sciences, Southern Medical University, Guangzhou, Guangdong Province, People's Republic of China
| | - Jia-Chun Qin
- Department of Medical Genetics, School of Basic Medical Sciences, Southern Medical University, Guangzhou, Guangdong Province, People's Republic of China
| | - Bi-Yan Chen
- Department of Genetic Metabolism, Prenatal Diagnostic Center, Maternal and Child Health Hospital of Guangxi Zhuang Autonomous Region, Nanning, People's Republic of China
| | - Xue-Xi Yang
- School of Laboratory Medical and Biotechnology, Southern Medical University, Guangzhou, Guangdong Province, People's Republic of China
| | - Hai-Ping Liu
- Neonatal Screening Center, Maternal and Child Health Hospital of Foshan, Foshan, Guangdong Province, People's Republic of China
| | - Wei-Xi Yuan
- Neonatal Screening Center, Maternal and Child Health Hospital of Foshan, Foshan, Guangdong Province, People's Republic of China
| | - Jian-Mei Zhong
- Department of Medical Genetics, School of Basic Medical Sciences, Southern Medical University, Guangzhou, Guangdong Province, People's Republic of China
| | - Li-Min Huang
- School of Laboratory Medical and Biotechnology, Southern Medical University, Guangzhou, Guangdong Province, People's Republic of China
| | - Wan-Jun Zhou
- Department of Medical Genetics, School of Basic Medical Sciences, Southern Medical University, Guangzhou, Guangdong Province, People's Republic of China
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