2012年1月4日,据《每日科学》报道,精神疾病,可以从许多层面进行描述,其中最传统的层面是沮丧经历的主观描述和使用评定量表量化抑郁症状。在过去二十年中,研究开发了其他一些策略,用于描述抑郁症的生物学基础,包括使用磁共振成像(MRI)测量大脑体积以及白细胞中的基因表达模式等。
在此期间,大量的研究试图找到特征性的基因,即能导致抑郁症反映在评定量表上人的情绪状态,能反映MRI测量到的大脑结构和功能的改变,以及能解释抑郁症患者验尸报告中脑组织的基因表达模式。
因此,如果能试图找到一个或数个基因,能解释所有这些搜集的不同类型信息所组合出的"全貌",这将会是怎么情况?这正是David Glahn博士(耶鲁大学和哈特福德医院生活研究所)和他的同事们想要试图去做的。
"他们提供了一个非常激动人心的策略,将我们在试图鉴定出风险基因的过程中搜集的各种类型的临床研究数据结合起来,"John Krystal说,《生物精神病学》(Biological Psychiatry)的编辑。
他们的工作定位了一个基因,称为RNF123,它可能在严重抑郁症中发挥着作用。
他们有两个明确的目标:描述一种新方法从基因对疾病的"重要性"方面将脑结构和功能的测量进行排名,定位抑郁症的候选基因。
"我们试图找出一种方法能将生物学测量与(精神科)疾病风险联系起来,"John Blangero博士说,德克萨斯州生物医学研究所基因组学计算中心主任。"在我们首次将这个方法应用于严重抑郁症时,我们实际上确实发现了一些令人兴奋的东西。"
尽管先前RNF123并没有与抑郁症联系起来,但它已被证明能够影响大脑中的海马,在严重抑郁症患者中被改变了。
"我们认为,生物学测量更接近于大脑疾病进展潜藏的机制。然而,最终我们感兴趣的是主观经验和精神疾病相关的功能障碍,"Krystal补充道。 "在这项研究中采用的方法可能有助于将所有这些信息利用起来,有希望提高我们确定导致抑郁症或可能靶向治疗基因的能力。"
Glahn说,"我们还需要进行更多的研究来确定这确实是一个本垒基因,但我们已经有了一个很好的候选基因。尽管这在抑郁症研究中很难。"(生物谷bioon.com)
doi:10.1016/j.biopsych.2011.08.022
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High Dimensional Endophenotype Ranking in the Search for Major Depression Risk Genes
David C. Glahn, Joanne E. Curran, Anderson M. Winkler, Melanie A. Carless, Jack W. Kent, Jac C. Charlesworth, Matthew P. Johnson, Harald H.H. Göring, Shelley A. Cole, Thomas D. Dyer, Eric K. Moses, Rene L. Olvera, Peter Kochunov, Ravi Duggirala, Peter T. Fox, Laura Almasy, John Blangero.
Abstract: Background: Despite overwhelming evidence that major depression is highly heritable, recent studies have localized only a single depression-related locus reaching genome-wide significance and have yet to identify a causal gene. Focusing on family-based studies of quantitative intermediate phenotypes or endophenotypes, in tandem with studies of unrelated individuals using categorical diagnoses, should improve the likelihood of identifying major depression genes. However, there is currently no empirically derived statistically rigorous method for selecting optimal endophentypes for mental illnesses. Here, we describe the endophenotype ranking value, a new objective index of the genetic utility of endophenotypes for any heritable illness. Methods: Applying endophenotype ranking value analysis to a high-dimensional set of over 11,000 traits drawn from behavioral/neurocognitive, neuroanatomic, and transcriptomic phenotypic domains, we identified a set of objective endophenotypes for recurrent major depression in a sample of Mexican American individuals (n = 1122) from large randomly selected extended pedigrees. Results: Top-ranked endophenotypes included the Beck Depression Inventory, bilateral ventral diencephalon volume, and expression levels of the RNF123 transcript. To illustrate the utility of endophentypes in this context, each of these traits were utlized along with disease status in bivariate linkage analysis. A genome-wide significant quantitative trait locus was localized on chromsome 4p15 (logarithm of odds = 3.5) exhibiting pleiotropic effects on both the endophenotype (lymphocyte-derived expression levels of the RNF123 gene) and disease risk. Conclusions: The wider use of quantitative endophenotypes, combined with unbiased methods for selecting among these measures, should spur new insights into the biological mechanisms that influence mental illnesses like major depression.