Exome sequencing and mutation identification in familial coeliac disease

乳糜泻(一种常见的肠道免疫疾病，由饮食中的小麦和谷物引起)在家庭中很常见，但这种遗传性最多有一半可以用我们目前对遗传风险因素的知识来解释。我们认为改变基因蛋白质编码序列的DNA序列突变可能有助于乳糜泻的遗传性。在其他疾病中也有这方面的证据。这些风险突变在人群中可能相对罕见。我们建议使用新技术对50个乳糜泻患者家族中的所有蛋白质编码基因(外显子组)进行测序。每个家庭至少有5人患有乳糜泻，1人有13人感染。我们将研究每个家庭的三个远亲个体，并寻找患有乳糜泻的人之间共享的突变。这将使我们能够从测序发现的数千种变异中缩小可能性。我们还将使用相对便宜的BeadChips来分析每个家庭中每个受影响个体的数十万种已知变异。这将为我们提供补充信息，显示受影响的个体之间共享基因组的哪些大区域。随后，我们将测试一个家庭中的所有个体(受影响的和未受影响的)，以寻找有希望的致病风险突变候选。一旦我们在几个基因中发现了新的致病风险突变，我们将在数千个样本中寻找不同的、可能是罕见的突变。在一个基因中发现多个突变可以进一步证明我们是在正确的轨道上，也为开发诊断和风险预测测试提供了信息。最后，我们还将在1万多名乳癌和健康人身上测试数千种突变。这将为疾病突变提供进一步的证据，并告诉我们关于每个突变的准确细节。在乳糜泻中识别罕见的高效果大小突变将为我们提供关于疾病如何发展的直接线索，并可能确定新的治疗靶点。我们先前已经证明，对乳糜泻的洞察可能会给出与其他慢性免疫疾病相关的洞察。这些罕见的突变通常会产生容易预测的后果，对于疾病的理解具有很高的价值。后续研究将调查这些突变对生物功能的影响。这项研究还可能产生与其他情况相关的方法学进步。

Coeliac disease (a common immune condition of the gut caused by reaction to dietary wheat and cereals) runs strongly in families, however at most half of this heritability can be explained by our current knowledge of inherited genetic risk factors.We think that mutations in DNA sequence that alters the protein coding sequence of genes may contribute to coeliac disease heritability. There is evidence for this in other diseases. These risk mutations are likely to be relatively rare in the population. We propose to use new technology to sequence all protein coding genes (the exome) in 50 selected very large multiply affected families with coeliac disease. Each family has at least 5 people with coeliac disease, one has 13 affected individuals. We will study three distantly related individuals per family and look for mutations shared between the people with coeliac disease. This will enable us to narrow down the possibilities from the many thousands of variants the sequencing uncovers.We will also use relatively cheap BeadChips to analyse hundreds of thousands of known variants in every affected individuals in each family. This will give us complementary information, showing which large regions of the genome are shared between the affected individuals.We will subsequently test all individuals (affected and unaffected) in a family for promising candidates for disease causing risk mutations.Once we have found new disease risk mutations in several genes, we will then look for different, possibly rare mutations in thousands of more samples. Finding multiple mutations in a gene gives further evidence that we are on the right track, and also provides information to develop diagnostic and risk-predicting tests. Finally, we will also test several thousand mutations in over ten thousand coeliac and healthy individuals. This will give further evidence to implicate disease mutations, and tell us precise details about each mutation. Identifying rare high effect size mutations in coeliac disease will give us direct leads into how disease develops and possibly identify new targets for treatments. We have previously shown that insights in coeliac disease are likely to give insights relevant to other chronic immune diseases.These rare mutations often have readily predictable consequences, and are of high value for disease understanding. Follow on studies will investigate the effects of these mutations on biological function. The study will likely also generate methodological advances relevant to other conditions.