Chromosomal Rearrangements and Cardiac Candidate Genes

本研究的目的是利用CHD患儿的染色体重排（CR）作为标记，以确定心脏形态发生中重要的新基因。这个提议的基本假设是，我们可以根据平衡易位断点的位置来识别对正常心脏发育至关重要的基因。此外，我们假设，其他染色体的变化，如添加或间质缺失，将有助于确定额外的剂量敏感基因的心脏发育的重要性。本研究的受试者将是向SCCOR报告心脏缺陷和可能进一步相关的先天性异常的儿童。我们将利用人类基因组计划的成果以及我们正在开发的新技术来表征参与基因组的区域。 SCCOR患者的染色体畸变。我们假设这些区域含有对正常心脏发育重要的基因。 我们将继续进行心脏候选基因的分子鉴定和分析，以便突变研究可以成为后续研究的重点。候选基因的表征将包括它们在小鼠和/或非洲爪蟾中的组织、空间和时间表达模式的描绘。我们将在模式生物中分离或鉴定这些候选基因的同源物。我们的具体目标包括：1）通过高分辨率细胞遗传学和分子细胞遗传学分析鉴定和表征CHD患者的CR; 2）使用 人基因组序列以鉴定易位断点（BP）; 3）表征来自正常染色体的BP处的基因组DNA以鉴定重排机制; 4）鉴定和表征在易位BP处被破坏或缺失的基因作为早期心脏形态发生的候选物;和5）确定候选基因中的突变是否与其他CHD患者的心脏缺陷相关。这代表了临床和基础研究的统一计划。它汇集了临床心脏病学，临床遗传学，细胞遗传学，分子生物学， 生物学和发育遗传学来研究基因组变异对CHD病因学的影响，以发现参与早期心脏发生基本途径的基因。

The goal in this proposal is to use chromosomal rearrangements (CRs) occurring in children with CHDs as signposts to identify novel genes important in cardiac morphogenesis. The underlying hypothesis of this proposal is that we can identify genes critical to normal cardiac development based upon their location in relation to breakpoints of balanced translocations. Further, we hypothesize that other chromosomal changes, such as additions or interstitial deletions will assist in the identification of additional dosage sensitive genes important to cardiac development. The subjects for this study will be children who present to the SCCOR with heart defects and possibly further associated congenital anomalies. We will utilize the fruits of the Human Genome Project as well as novel technology we are developing to characterize the regions involved in the chromosomal aberrations of SCCOR patients. We hypothesize that these regions harbor genes important to normal cardiac development. We will pursue the molecular identification and analysis of cardiac candidate genes such that mutation studies can be the focus of subsequent research studies. Characterization of the candidate genes will include the delineation of their tissue, spatial and temporal expression patterns in mouse and/or Xenopus. We will isolate or identify homologues of these candidate genes in model organisms. Our specific aims include: 1) identification and characterization of CRs in patients with CHD by high-resolution cytogenetics and molecular cytogenetic analysis; 2) development of PCR-based mapping strategies using the human genomic sequence to identify translocation breakpoints (BPs); 3) Characterization of the genomic DNA from normal chromosomes at the BPs in order to identify mechanisms of rearrangement; 4) identification and characterization of genes disrupted or deleted at the translocation BPs as candidates for early cardiac morphogenesis; and 5) determination of whether mutations in the candidate genes are associated with the cardiac defect in other patients with CHD. This represents a unified program of clinical and basic research. It brings together the disciplines of clinical cardiology, clinical genetics, cytogenetics, molecular biology and developmental genetics to examine the influence of genomic variation on the etiology of CHDs in our quest to discover genes involved in fundamental pathways during early cardiogenesis.