DIABETES IN HEMOCHROMATOSIS

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目及 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 本研究涉及两个具体目标：目标1。遗传性血色病铁负荷表型修饰基因的鉴定。目标2.确定影响血色素沉着症患者的葡萄糖耐受不良和临床明显糖尿病的机制。目的1我们将利用新的和以前确定的家系来确定铁过载引起的病态并发症的一致性模式，这些并发症是通过表型或基因型确定的。这些数据将与从专门小鼠品系获得的数据结合使用，以鉴定修饰血色病表型表达的候选基因。简而言之，小鼠遗传学将用于鉴定被认为影响肠铁吸收的候选基因和染色体区域。将比较与疾病相关发病率一致的血色素沉着症纯合子同胞集合，以确定它们是否在小鼠中鉴定的同线候选区域中共享单倍型。肝硬化、肝纤维化、转氨酶值升高（除铁过载外无任何可识别原因），X线片证实掌指关节的血色病关节病。在目标2中，我们将利用新获得的血色病家系来确定葡萄糖耐受不良、胰岛素分泌受损和临床明显糖尿病的患病率。我们将确定胰岛素分泌缺陷是否与铁过载相关。然后我们将确定是否只有当胰岛素抵抗叠加在铁介导的胰岛素分泌缺陷上时才发生糖尿病。最后，我们将确定肝葡萄糖的产生对血色素沉着症糖尿病的贡献。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. This study addresses two specific aims: Aim 1. Identify genes that modify the iron-loading phenotype of hereditary hemochromatosis. Aim 2. Determine the mechanism(s) responsible for the glucose intolerance and clinically evident diabetes that affect patients with hemochromatosis.For Aim 1 we will utilize both new and previously ascertained pedigrees to define patterns of concordance for morbid complications due to iron overload among relatives (mainly sibling pairs) who have been identified either by phenotype or genotype to have hemochromatosis. These data will be used in conjunction with data obtained from specialized mouse strains to identify gene candidates which modify the phenotypic expression of hemochromatosis. Briefly, mouse genetics will be used to identify candidate genes and chromosomal regions believed to influence intestinal iron absorption. Hemochromatosis homozygote sibling sets concordant for disease related morbidity will be compared to determine if they share haplotypes in syntenic candidate regions identified in the mouse.Morbid complications due to iron overload will be defined clinically as: cirrhosis, hepatic fibrosis, elevated aminotransferase values in the absence of any identifiable cause other than iron overload, and radiographically confirmed hemochromatosis arthropathy of the metacarpal-phalangeal joints. In Aim 2 we will utilize newly acquired hemochromatosis pedigrees to determine the prevalence of glucose intolerance, impaired insulin secretion and clinically evident diabetes. We will determine if a defect in insulin secretion correlates with iron overload. We will then determine if diabetes occurs only when insulin resistance is superimposed on an iron-mediated defect in insulin secretion. Finally, we will determine the contribution of hepatic glucose production to the diabetes of hemochromatosis.