中文摘要：

表观遗传学是研究DNA序列未发生改变的情况下，基因表达的可遗传变异的一门学科，其涉及的机制主要包括DNA甲基化、组蛋白修饰和MicroRNA等。系统性硬皮病是一种累及皮肤及多种器官的自身免疫性结缔组织疾病，其发病机制复杂。近年来，有关系统性硬皮病表观遗传学机制的研究取得一定进展，特别是DNA甲基化、组蛋白修饰参与系统性硬皮病自身抗体的产生和胶原合成异常，如有研究发现，患者CD4＋T细胞基因调控序列甲基化水平的降低导致CD70和CD40L表达升高，从而参与系统性硬皮病发病；Flil基因启动子区域组蛋白的异常修饰导致Flil表达下降，胶原合成增加。基因低甲基化、组蛋白低乙酰化和MicroRNA修饰可能会成为系统性硬皮病早期生物学标记和治疗目标。

英文摘要：

Epigenetics is a discipline to study inheritable gene expression without changes in DNA sequence. The mechanisms of epigenetics include DNA methylation, histone modifications and microRNAs. Systemic scleroderma （SSc） is an autoimmune connective tissue disease involving the skin and various organs. The pathogenesis of SSc is complex. Recently, some progress has been made in epigenetic mechanisms in SSc. DNA methylation and histone modifications have been shown to be involved in autoantibody production and abnormal collagen synthesis in SSc. In detail, the demethylation of regulatory sequences may lead to increased expression of CD70 and CD40L in CD4＋ T cells from patients with SSc, which in turn contributes to the development of SSc; the abnormal histone modification of Flil gene promoter region may cause decreased expression of Flil and increased collagen synthesis. Gene hypomethylation, histone deacetylation and microRNA modification may serve as early biological markers and therapeutic targets of SSc.