Prenatal diagnosis through selective DNA amplification

描述（由申请人提供）：尽管对常见染色体异常进行无创产前诊断的临床需求广泛且持续存在，但目前尚无方法进行此类诊断。最近的研究表明，从母体血液和子宫颈的非侵入性样本中获取胎儿DNA的可行性，为非侵入性产前诊断提供了一条有吸引力的途径。然而，常规使用非侵入性获得的样本仍然难以捉摸，因为胎儿DNA存在于与高比例的“污染”母体DNA的混合物中，这使得检测胎儿特异性序列具有挑战性。我们已经开发了一种新的方法，利用差异甲基化，允许从含有高比例非滋养层DNA的混合物中选择性扩增滋养层特异性序列。我们假设这种方法可以与其他技术结合使用，使用来自母体血浆或母体宫颈样本等非侵入性来源的DNA来诊断染色体异常。本申请中提出的工作的总体目标是：1)提供可通过我们的方法扩增的滋养细胞特异性DNA片段的大规模“目录”；2)探索两种不同方法的可行性，通过选择性扩增的胎儿DNA片段可用于胎儿非整倍体的无创检测。我们预计，这些目标的实现将铺平道路，为胎儿非整倍体新的，非侵入性产前检查的发展。当这些方法成为可能时，它们将彻底改变产前诊断，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.