TWO X-LINKED GENES THAT REGULATE MINERAL HOMEOSTASIS

目标是鉴定、克隆、测序和表征两个基因， 控制儿童体内矿物质平衡的人类X染色体。 虽然编码蛋白的功能仍有待确定， 我们对与两个基因座相关的缺陷患者的临床研究， 研究表明，一种是甲状旁腺发育所必需， 另一个控制磷酸盐的体内平衡。 具体而言，缺陷导致 X连锁隐性特发性甲状旁腺功能减退症（HPT）和X连锁 低磷酸盐血症（HYP）。 我们已经绘制出了受影响的 家庭，包括当地人口的独特资源， 相应的基因存在于重叠的YAC克隆中， 手 该提案的具体目标首先侧重于隔离 来自YAC的两种疾病的候选基因， 本地化。 将使用几种方案，包括新的重组- 基于在与cDNA序列同源的位点截短YAC的方法， 以及基于CpG的靶向测序的候选基因推断 岛和长带的基因组DNA窝藏的基因座。 后 候选基因的分离，研究将转向识别 真正的候选人，伴随着突变的变化分析， 受影响的个人。 这些研究既可以作为一种途径， 将基因型变化与疾病的严重程度和病理生理学相关联， 疾病，并作为表征蛋白质产物的前奏， 基因修饰或破坏的影响。

The goal is to identify, clone, sequence, and characterize two genes on the human X chromosome that control mineral homeostasis in children. Although the function of the encoded proteins remains to be determined, our clinical studies of patients with defects linked to the two loci of interest show that one is essential for parathyroid gland development and the other controls phosphate homeostasis. Specifically, the defects cause X-linked recessive idiopathic hypoparathyroidism (HPT) and X-linked hypophosphatenia (HYP). We have mapped the disease loci in affected families, including unique resources in local populations, and the corresponding genes are present in overlapping YAC clones that are on hand. The specific aims of the proposal focus first on the isolation of candidate genes for the two diseases from YACs in which they are localized. Several protocols will be used, including a new recombination- based method that truncates a YAC at sites homologous to cDNA sequences, and inference of candidate genes based on targeted sequencing of CpG islands and long tracts of genomic DNA harboring the loci. Following the isolation of candidate genes, studies would turn to identification of the true candidates, with accompanying analysis of the mutational changes in affected individuals. These studies would serve both as a route to correlate genotypic changes with the severity and pathophysiology of the disease, and as a prelude to characterization of the protein products and the effects of gene modification or disruption.