Epigenetic and LncRNA-Mediated Regulation of X Chromosome Inactivation and Its Impact on Pathogenesis

Purpose of Review In multicellular organisms, development of genetic sex determination leads to gene dosage imbalances between the sex chromosomes and the autosomes and between the sexes. In mammals with XY-based system, a dosage compensation mechanism called X chromosome inactivation (XCI) balances gene expression from unequal number of sex chromosomes between the homogametic (XX) females and heterogametic (XY) males. XCI-mediated dosage compensation involves transcriptional silencing of one of the two X chromosomes in female cells and is tightly mediated during early development.