广西地区未知α-珠蛋白基因突变的分子鉴定

α-Thalassemia is one of the most serious public health threats facing the Guangxi people. It is a heterogeneous group of death or disabling inherited disorders characterized by the reduced or absent synthesis of α-globin chains. α-Globin is generated hemolyticanemia that caused by genetic abnormalities of the disease most a gene deletion, α-gene deletion of the number and the lack of α-globin chain. Common α-thalassemia gene mutations have been elucidated, but there are still a certain number of clinical cases that can not be diagnosed by conventional molecular detection techniques. We speculate that these patients may carry rare or unknown α-thalassemia gene mutations.In this proposal,we aim to use large-scale Guangxi-regional thalassemia genetic resources and deeply study the molecular basis of these cases. We intend to expand system study for diagnosing these cases by collecting 100 nuclear families that hematology phenotype of probands is positive and α-globin gene mutations are not detected by conventional molecular diagnosis methods. We analysis the situation of alpha-globin gene and confirm these cases whether carried unknown or rare mutations by integrally using DNA sequencing technology, multiple ligation-dependent probe amplification (MLPA) technology and array comparative genomic hybridization (aCGH) technology. Meanwhile we perform the molecular identification and functional analysis of these mutations. Fulfillment of the above goals will help to enrich the α-globin gene mutations spectrum and meanwhile offer the necessary technical expertise for prevention and control of α-thalassemia the Guangxi region.

α-地中海贫血（α-地贫）是广西地区严重威胁人类健康的致死致残性遗传性血液病，其发病原因是α-珠蛋白基因缺陷，导致α-珠蛋白合成不足，引发溶血性贫血。常见的α-地贫基因突变已被阐明，但目前临床上仍存在一定数量的病例，用常规分子检测技术无法诊断，推测此类病例携带罕见或未知的α-地贫基因突变。本项目拟利用广西地区大样本地贫遗传资源，针对此类病例进行分子基础的深入研究，通过收集100个先证者为血液学表型阳性而常规分子诊断未检出α-珠蛋白基因突变的核心家系，综合运用DNA测序技术、多重连接探针扩增（MLPA）技术、芯片比较基因组杂交（aCGH）技术等方法，对样本的α-珠蛋白基因结构进行分析，从而鉴定其所携带的罕见或未知突变，并对突变基因的性质和功能进行探讨。本项目将丰富中国人群α-珠蛋白基因突变谱，为罕见型α-地中海贫血的干预提供依据。

α-地中海贫血（α-地贫）是广西地区严重威胁人类健康的致死致残性遗传性血液病，其发病原因是α-珠蛋白基因缺陷，导致α-珠蛋白合成不足，引发溶血性贫血。95%的α-地贫基因突变已被阐明，但目前临床上仍存在一定数量的病例，用常规分子检测技术无法诊断，推测此类病例携带罕见或未知的α-地贫基因突变。本项目共收集105个临床表型拟罕见α-地贫基因变异的核心家系，采用gap-PCR及反向斑点杂交技术对样品进行常规变异的排查，随后通过MLPA和测序及Array SNP技术进一步进行α-珠蛋白基因缺失、点突变、CNV分析，获得大量有价值的基因变异信息；研究工作主要分为的缺失断裂点位置的精确定位及研究变异对α-珠蛋白基因转录水平（mRNA）的影响及相应的数据分析。目前已完成了alpha珠蛋白基因新变异中一个家系分析及功能分析，对其中α-珠蛋白基因簇大片段缺失的进行基因芯片扫描，明确了缺失片段的位置及大小。其中一个家系已经通过PCR技术找出精确的缺失断裂点位置，并研究了新变异对α-珠蛋白基因转录水平（mRNA）的影响，本项目培养硕士研究生1名，发表论文6篇，其中SCI二篇。本项目丰富中国人群α-珠蛋白基因突变谱，为罕见型α-地中海贫血的干预提供依据。