Exploring the Mechanism of Genetic Reversion in Ichthyosis with Confetti

项目摘要/摘要 反转马赛克病(Rm)是一种非常罕见的自发致病突变事件。 矫正后，形成正常组织区域。然而，在五彩纸屑鱼鳞病(IWC)中，严重的 由影响中间丝蛋白尾部结构域的显性突变引起的皮肤疾病 角蛋白10(KRT10)或角蛋白1(KRT1)，患者会出现数百至数千个回复斑块 正常皮肤，每一种都是由拷贝中性杂合性丢失(CN- LOH)，可能是由于基于同源的有丝分裂重组。这种频率的戏剧性增加 一个原本罕见的事件为探索基因逆转的机制提供了一个独特的机会， 目前人们对此知之甚少。在IWC中，回复斑块的数量和大小随着时间的推移而增长， 这表明突变细胞比邻近的突变细胞具有选择性优势。值得注意的是， KRT10或KRT1其他区域的突变导致一种独特的疾病，称为表皮松解症 鱼鳞病(EI)，其特征是没有临床或遗传证据的同样严重的皮肤表型 Rm.这意味着KRT10和KRT1的尾部结构域在潜在的调控中具有独特的作用 DNA重组和修复。这个项目的目的是确定基因突变的频率 IWC中的逆转是突变KRT10和KRT1对同源碱基影响的直接结果 重组，以及突变克隆和突变克隆之间的细胞竞争是否在 回变皮肤的形成和扩张。为了探索这些可能性，我们开发了 一种条件敲入的IWC小鼠模型，概括了IWC的临床和组织学特征 疾病，更重要的是，通过LOH表现出回复马赛克的证据。我们将利用这一点 小鼠模型以及询问杂合性缺失、DNA损伤和修复以及细胞的比率的工具 竞争，以探索IWC中频繁出现的遗传自我纠正的机制 皮肤。阐明基因逆转的机制有可能产生新的治疗方法 防治遗传性和自发性遗传性疾病的策略，包括诱发或改变的方法 返回事件的速率。

PROJECT SUMMARY / ABSTRACT Revertant mosaicism (RM) is a very rare event by which pathogenic mutations are spontaneously corrected, giving rise to areas of normal tissue. However, in ichthyosis with confetti (IWC), a severe skin disorder due to dominant mutations affecting the tail domains of intermediate filament proteins keratin 10 (KRT10) or keratin 1 (KRT1), patients develop hundreds to thousands of revertant macules of normal skin, each arising from independent events of copy-neutral loss-of-heterozygosity (CN- LOH), likely due to homology-based mitotic recombination. This dramatic increase in the frequency of an otherwise rare event provides a unique opportunity to explore mechanisms of genetic reversion, which are currently poorly understood. In IWC, revertant patches grow in number and size over time, suggesting that revertant cells acquire a selective advantage over neighboring mutant cells. Notably, mutations in other domains of KRT10 or KRT1 lead to a distinct disorder known as epidermolytic ichthyosis (EI), which features an equally severe skin phenotype without clinical or genetic evidence of RM. This implicates a unique role of the tail domain of KRT10 and KRT1 in potentially regulating DNA recombination and repair. This project aims to determine whether the frequency of genetic reversion in IWC is a direct consequence of mutant KRT10 and KRT1 effects on homology-bases recombination, and whether cellular competition between revertant and mutant clones play a role in the formation and the expansion of revertant skin. To explore these possibilities, we have developed a conditional knock-in mouse model of IWC, which recapitulates clinical and histologic features of the disease, and, more importantly, shows evidence revertant mosaicism via LOH. We will employ this murine model alongside tools to interrogate rates of LOH, DNA damage and repair, and cellular competition, to explore the mechanisms underlying the frequent genetic self-correction seen in IWC skin. Elucidating the mechanisms of genetic reversion has potential to generate new therapeutic strategies against inherited and spontaneous genetic disorders, including methods to induce or alter the rate of reversion events.