基于多重cSMART技术的β地中海贫血无创产前检测研究

The rate of β-Thalassemia in the southern of China has reached up to 1% - 7%. The offsprings of the couples who are both carriers have 25% chance of suffering from moderate or heavy β-Thalassemia. Thus, it would bring great pain and economic burden to the patients and the families. Conventional invasive prenatal diagnosis can effectively prevent children with defect born, but there is a risk of spontaneous abortion. In the research of noninvasive prenatal diagnosis of β-Thalassemia with low level fetal-derived free DNA , the method based on SNP haplotyping is limited in clinical application due to its complex analytical approach and multiple platforms. Our research is about to adapt our independent cSMART technology, which aims at hot mutations of β-Thalassemia pathogenic genes ,we design back-to-back specific amplification primers to greatly increase the efficiency of original seqence,the introduction of the high-performance barcode system would eliminate the deviation caused by PCR amplification,and the multiple primers covered hot mutations would detect over 95% mutations in Chinese individuals with β-Thalassemia, in the condition of avoiding personalized primers design. Thus, we will establish a extensively used, reliable, rapid and economic noninvasive prenatal detection for β-Thalassemia, which would avoid the risk of abortion from the conventional invasive prenatal diagnosis and has great significance in preventing and controlling β-Thalassemia.

我国南方人群β地贫携带率高达1%-7%，携带者婚配有25%概率生育中、重型地贫患儿，给患者和家庭带来巨大的痛苦和经济负担。有创产前诊断可有效防止患儿出生，但存在一定的流产和感染风险。目前采用孕妇外周血浆游离DNA的β地贫无创产前诊断研究，由于胎源DNA含量低，基于SNP单体型的方法存在依赖多个平台且分析方法复杂等诸多不足，限制了其在临床中的应用。本研究拟采用自主研发的cSMART技术，针对我国南方人群β地贫致病基因突变热点，设计背靠背的PCR特异性扩增引物，极大地增加了原始序列的利用率，高效barcode系统的引入则消除了因PCR扩增引起的序列偏移，多重引物扩增可一次性涵盖突变热点区域，在不进行个性化引物定制的前提下,能够一次性检测95%以上β地贫突变。因此，本研究将建立一种临床适用广泛、准确、快速、低成本的β地贫无创产前检测方法，可有效避免有创诊断风险，对地贫的防控具有重大意义。

β地贫为我国华南地区最常见的单基因病之一，会带来巨大的痛苦和经济负担。本研究通过实验和分析方法的升级，开发了一种新的多重cSMART方法，实现了中国人β地贫常见点突变位点的全覆盖。通过在130例地贫高风险家系中，进行常规有创产前与cSMART检测，结果提示多重cSMART方法有较好的临床表现和应用前景。