University of Bristol and Bristol Eye Hospital, Bristol, UK.
Philos Trans R Soc Lond B Biol Sci. 2011 Apr 27;366(1568):1234-49. doi: 10.1098/rstb.2010.0227.
Cataracts (opacities of the lens) are frequent in the elderly, but rare in paediatric practice. Congenital cataracts (in industrialized countries) are mainly caused by mutations affecting lens development. Much of our knowledge about the underlying mechanisms of cataractogenesis has come from the genetic analysis of affected families: there are contributions from genes coding for transcription factors (such as FoxE3, Maf, Pitx3) and structural proteins such as crystallins or connexins. In addition, there are contributions from enzymes affecting sugar pathways (particularly the galactose pathway) and from a quite unexpected area: axon guidance molecules like ephrins and their receptors. Cataractous mouse lenses can be identified easily by visual inspection, and a remarkable number of mutant lines have now been characterized. Generally, most of the mouse mutants show a similar phenotype to their human counterparts; however, there are some remarkable differences. It should be noted that many mutations affect genes that are expressed not only in the lens, but also in tissues and organs outside the eye. There is increasing evidence for pleiotropic effects of these genes, and increasing consideration that cataracts may act as early and readily detectable biomarkers for a number of systemic syndromes.
白内障（晶状体混浊）在老年人中很常见，但在儿科实践中很少见。先天性白内障（在工业化国家）主要由影响晶状体发育的突变引起。我们对白内障形成的潜在机制的了解主要来自受影响家族的遗传分析：转录因子（如 FoxE3、Maf、Pitx3）和结构蛋白（如晶体蛋白或连接蛋白）的基因都有贡献。此外，还来自影响糖代谢途径（特别是半乳糖途径）的酶和一个出人意料的领域：轴突导向分子，如 ephrins 及其受体。白内障小鼠晶状体可以通过肉眼轻松识别，并且现在已经对大量突变系进行了表征。通常，大多数小鼠突变体表现出与人类突变体相似的表型；然而，也有一些显著的差异。值得注意的是，许多突变影响不仅在晶状体中表达，而且在眼睛以外的组织和器官中表达的基因。这些基因的多效性影响的证据越来越多，并且越来越多的人认为白内障可能是许多全身性综合征的早期且易于检测的生物标志物。
