GENES DELETED IN THE 13Q SYNDROME

13号染色体长臂杂合性缺失的患者 取决于被删除片段的可变表型，范围为 轻度精神发育迟滞和轻微变形特征 在生命早期通常致命的畸形(“13q-”综合征)。 我们有初步证据表明删除了一个小的(小于1 带q32中的百万碱基)区域导致严重表型，通常 涉及大脑、心脏、肾脏和手指的畸形。《长河》 本项目的学期目标是分离和表征 存在一个或多个我们假设的发育重要基因 在这个地区。这将通过以下具体的 目标： 1.确定染色体13q的临界区。我们将继续使用 患者来源的细胞系确定最小共同缺失区域 在13q缺失的患者中有严重的表型。 同时，我们将构建该序列的YAC、COSMID和PI重叠群 “危急地区”。 2.对临界区基因进行分离和测序。外显子 以及一种新的消减杂交方法，该方法 我们在我们机构开发的将被用来分离 位于关键区域。 3.选择候选基因。基因很可能在 13q综合征患者的发育过程受阻 将通过同源搜索和对组织的研究来选择 Northern和原位杂交检测基因表达的分布和时间 杂交分析。 4.分离和鉴定候选cDNA的小鼠同源基因。这个 候选基因的小鼠同源基因将被分离，时间和 他们的表达的组织分布将被调查。同音词 小鼠基因组的区域将被识别和检查是否可能 相似的发育突变体。 5.寻找孤立性全前脑畸形患者的微缺失。 一组高度多态的标记来自 临界区将用于筛查慢性阻塞性肺疾病患者的微缺失 孤立性全前脑畸形。这些患者的DNA样本和他们的 家长将通过合作向我们提供联系。

Patients with heterozygous deletions of the long arm of chromosome 13 have a variable phenotype that depends upon the deleted segment and ranges from mild mental retardation and minor dysmorphic features to major malformations which are usually lethal in early life (the "13q-"syndrome). We have preliminary evidence that the deletion of a small (less than 1 megabase) region in band q32 results in the severe phenotype, typiCally involving malformations of the brain, heart, kidneys and digits. The long term goal of this project is to isolate and characterize the developmentally important gene or genes which we hypothesize are present in this region. This will be accomplished through the following specific aims: 1. Define the critical region in chromosome 13q. We will continue to use patient derived cell lines to define the minimal common region of deletion in patients with 13q deletions who have the severe,phenotype. Simultaneously, we will construct YAC, cosmid and PI contigs of this "critical region'. 2. Isolate and sequence genes within the critical region. Exon amplification as well as a new method of subtractive hybridization which we have developed at our institution will be used to isolate genes which are located in the critical region. 3. Select candidate genes. Genes likely to have a role in the developmental processes which are disrupted in the 13q syndrome patients will be selected by homology searches as well as studies of the tissue distribution and timing of expression by Northern and by in situ hybridization analysis. 4. Isolate and characterize murine homologues of candidate cDNAs. The murine homologues of candidate genes will be isolated, and the timing and tissue distribution of their expression will be investigated. The syntenic region of the mouse genome will be identified and examined for possible similar developmental mutants. 5. Look for microdeletions in patients with isolated holoprosencephaly. PCR with a collection of highly polymorphic markers from within the critical region will be used to screen for microdeletions in patients with isolated holoprosencephaly. DNA samples from such patients and their parents will be made available to us through a collaboration.