Zhong Zeyan, Zheng Ganwei, Zhu Dina, Liu Yongqiong, Lin Zezhang, Guan Zhiyang, Xiong Fu, Chen Jianhong, Shang Xuan
Department of Medical Genetics and Prenatal Diagnosis, Huizhou First Maternal and Child Health Care Hospital, Huizhou, Guangdong, China.
Department of Medical Genetics, School of Basic Medical Sciences, Southern Medical University, Guangzhou, Guangdong, 510515, China.
Orphanet J Rare Dis. 2025 Apr 2;20(1):153. doi: 10.1186/s13023-025-03701-8.
Thalassemia is one of the most prevalent monogenic disorders in tropical and subtropical regions, imposing significant familial and social burdens on local populations. It is caused by point mutations or structural variations (SVs) in the α- or β-globin gene clusters. Due to the complex structure, full characterization of SVs has always been the focus and difficulty of molecular diagnosis of thalassemia patients.
Peripheral blood of a Chinese boy with β-thalassemia intermedia phenotype and his family members were collected. Multiplex ligation dependent probe amplification (MLPA), long-read sequencing (LRS) and Sanger sequencing were used to analyze the variant in this family.
A novel large duplication (αααα) was identified using LRS technique and validated by Sanger sequencing. Additionally, we conducted a systematic review of known SVs and evaluated the advantages and disadvantages of various methods in analyzing complex SVs.
Our study identified a novel SV in the α-globin gene cluster and demonstrated that LRS was a superior approach for detecting novel rare SVs. The appropriate use of LRS significantly improves diagnostic accuracy when conventional methods are not capable of completely identifying complex SVs.
地中海贫血是热带和亚热带地区最常见的单基因疾病之一，给当地人群带来了巨大的家庭和社会负担。它由α或β珠蛋白基因簇中的点突变或结构变异（SVs）引起。由于结构复杂，SVs的全面表征一直是地中海贫血患者分子诊断的重点和难点。
收集了一名具有中间型β地中海贫血表型的中国男孩及其家庭成员的外周血。采用多重连接依赖探针扩增（MLPA）、长读长测序（LRS）和桑格测序对该家系中的变异进行分析。
使用LRS技术鉴定出一个新的大片段重复（αααα），并通过桑格测序进行了验证。此外，我们对已知的SVs进行了系统综述，并评估了各种方法在分析复杂SVs方面的优缺点。
我们的研究在α珠蛋白基因簇中鉴定出一种新的SV，并证明LRS是检测新型罕见SVs的优越方法。当传统方法无法完全识别复杂的SVs时，适当使用LRS可显著提高诊断准确性。
