MicroRNAs (miRNA) are small-non coding RNAs endowed with great regulatory power, thus playing key roles not only in almost all physiological pathways, but also in the pathogenesis of several diseases. Surprisingly, genomic distribution analysis revealed the highest density of miRNA sequences on the X chromosome; this evolutionary conserved mammalian feature equips females with a larger miRNA machinery than males. However, miRNAs contribution to some X-related conditions, properties or functions is still poorly explored. With the aim to support and focus research in the field, this review analyzes the literature and databases about X-linked miRNAs, trying to understand how miRNAs could contribute to emerging gender-biased functions and pathological mechanisms, such as immunity and cancer. A fine map of miRNA sequences on the X chromosome is reported, and their known functions are discussed; in addition, bioinformatics functional analyses of the whole X-linked miRNA targetome (predicted and validated) were performed. The emerging scenario points to different gaps in the knowledge that should be filled with future experimental investigations, also in terms of possible implications and pathological perspectives for X chromosome aneuploidy syndromes, such as Turner and Klinefelter syndromes.

中文翻译：

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microRNA 可以告诉我们有关人类 X 染色体的信息。


MicroRNA（miRNA）是一种小非编码RNA，具有强大的调节能力，因此不仅在几乎所有生理途径中发挥着关键作用，而且在多种疾病的发病机制中也发挥着关键作用。令人惊讶的是，基因组分布分析揭示了 X 染色体上 miRNA 序列的密度最高；这种进化上保守的哺乳动物特征使雌性拥有比雄性更大的 miRNA 机制。然而，miRNA 对某些 X 相关条件、特性或功能的贡献仍知之甚少。为了支持和集中该领域的研究，这篇综述分析了有关 X 连锁 miRNA 的文献和数据库，试图了解 miRNA 如何促进新兴的性别偏见功能和病理机制，例如免疫和癌症。报告了 X 染色体上 miRNA 序列的精细图谱，并讨论了它们的已知功能；此外，还对整个 X 连锁 miRNA 目标组进行了生物信息学功能分析（预测和验证）。新出现的情况指出了未来实验研究应填补的知识空白，以及 X 染色体非整倍体综合征（如特纳综合征和克兰费尔特综合征）的可能影响和病理学观点。