Prenatal diagnosis through selective DNA amplification

描述(申请人提供)：尽管临床上普遍和持久地需要对常见的染色体异常进行非侵入性产前诊断，但目前还没有进行这种诊断的方法。最近的工作表明，从非侵入性的母血和宫颈样本中获取胎儿DNA的可行性，为非侵入性产前诊断提供了一个有吸引力的途径。然而，非侵入性获取的样本的常规使用仍然难以捉摸，因为胎儿DNA与高比例的“污染”的母体DNA存在混合，这使得检测胎儿特定序列具有挑战性。我们已经开发了一种新的方法，利用差异甲基化来允许从含有高比例非滋养细胞DNA的混合物中选择性地扩增滋养细胞特异的序列。我们假设，这种方法可以与其他技术结合使用，使用来自非侵入性来源的DNA来诊断染色体异常，例如母体血浆或母体宫颈样本。本申请中提出的工作的总体目标是：1)提供可用我们的方法扩增的滋养层特定DNA片段的大规模“目录”；2)探索两种不同方法的可行性，通过这两种方法选择性扩增的胎儿DNA片段可用于非侵入性检测胎儿非整倍体。我们预计，这些目标的实现将为发展新的、非侵入性的胎儿非整倍体产前检测铺平道路。当这些方法可用时，它们将使产前诊断发生革命性变化，并将成为改善产前护理的一个重要里程碑。

DESCRIPTION (provided by applicant): Despite the widespread and persistent clinical need for non-invasive prenatal diagnosis of common chromosome abnormalities, methods to perform such diagnoses are not currently available. Recent work showing the feasibility of obtaining fetal DNA from non-invasive samples of maternal blood as well as from the uterine cervix offers an attractive avenue through which non-invasive prenatal diagnosis might be performed. However, the routine use of non-invasively obtained samples remains elusive because the fetal DNA exists in a mixture with a high proportion of "contaminating" maternal DNA, making it challenging to detect fetal specific sequences. We have developed novel method that makes use of differential methylation to allow for the selective amplification of trophoblast-specific sequences from mixtures that contain a high proportion of non- trophoblast DNA. We hypothesize that this method can be used in conjunction with other technologies to diagnose chromosome abnormalities using DNA derived from non-invasive sources such as maternal plasma or maternal cervical samples. The overall goals of the work proposed in this application are to 1) provide a large-scale "catalog" of trophoblast specific DNA segments that can be amplified by our method and 2) to explore the feasibility of two different methods by which selectively amplified fetal DNA segments might be used for non-invasive detection of fetal aneuploidy. We anticipate that the achievement of these aims will pave the way to the development of new, non-invasive prenatal tests for fetal aneuploidy. When and if such methods become available, they will revolutionize prenatal diagnosis and will represent a major milestone in the improvement of prenatal care.