MOLECULAR AND CYTOGENETIC DELINEATIONS OF 22Q11 DELETIONS

有VCFS和22 q11风险的患者人群。11.23是 非常大。 因此，一种基于DNA的快速筛查方法， 将需要删除风险高的个人。 我们建议 开发和应用基于多重PCR的筛选试验， 多态性DNA标记 有删除风险的个人将被 通过荧光原位杂交（FISH）进一步筛选， 22q11.2特异性粘粒克隆，其跨越并侧翼于VCFS关键位点 地区 利用多个探针的同时杂交， 间期核将帮助我们估计缺失的程度， 选择的个人。 我们将测试的假设，差异在 内缺失的大小、位置、亲本或来源以及病因学 22 q11解释了在受影响的 家庭成员可能会因继承的家庭规模的变化而产生。 减数分裂期间的缺失。 为了验证这一假设，我们将 缺失的大小和位置与临床结果（核心A）， 发现的基因（项目1）及其表达模式（项目2） 2）。 我们将比较多个受影响家庭中缺失的大小 成员和测试的印记效应，通过确定父母的 来源于缺失的患者。 最后，我们提出22 q11可能 通过着丝粒与其他近端着丝粒染色体交换重新排列。 我们将研究这种“隐性易位”的流行情况， 与22q11.2缺失相关的机制。 最后，我们建议， VCFS表型的孤立特征，特别是腭裂和/或 VIP，可能是由VCFS中的单个基因的异常引起的-缺失 地区 为了验证这一假设，我们将测试一组孤立的裂缝， 腭患者的缺失的存在，并检查证据 在22q11.21->22q11.23中存在腭裂位点， 检查腭裂患者或家庭的基因座关联。

The population of patients at-risk for VCFS and 22q11.->11.23 is extremely large. Therefore, a rapid DNA-based screening method to detect individuals at high risk for deletions will be required. We propose to develop and apply a multiplex PCR-based screening assay using highly polymorphic DNA markers. Individuals at risk for deletions will be further screened by fluorescence in situ hybridization (FISH) utilizing 22q11.2-specific cosmid clones which span and flank the VCFS critical region. Utilization of simultaneous hybridization of multiple probes to interphase nuclei will help us to estimate the extent of deletions for selected individuals. We will test the hypothesis that difference in the size, location, parent or origin, and etiology of the deletions within 22q11 account for the phenotypic variability observed between affected members of families may result from change in the size of an inherited deletion during meiosis. To test this hypothesis, we will correlate the size and location of the deletions with the clinical findings (Core A), the genes discovered (Project 1) and their expression pattern (Project 2). We will compare the size of deletions in multiple affected family members and test for imprinting effects by determining the parent of origin in patients with deletions. Finally, we propose that 22q11 may rearrange by centromeric exchange with other acrocentric chromosomes. We will examine the prevalence of such "cryptic translocation" as a mechanism associated with 22q11.2 deletions. Finally, we propose that isolated features of the VCFS phenotype, especially cleft palate and/or VIP, may be caused by abnormalities of a single gene in the VCFS-deletion region. To test this hypothesis we will test a cohort of isolated cleft palate patients for the presence of deletions and examine the evidence for the presence of a cleft palate locus in 22q11.21->22q11.23 by examining locus associations in cleft palate patients or families.