X chromosome skewness in neurological disorders

X-chromosome inactivation (XCI) is an epigenetic strategy through wich one X chromosome in mammalian female cells is silenced to balances X-linked gene quantity between male and female. Inactivation of the similar X is preserved during somatic cell divisions، resulting in mosaic females with cell populations incloudings one or the thesecond X active. The procedure is usually random such that approximately equal quantities of cells express each X chromosome. Cellular mosaicism prepares females with a noteworthy biological advantage. As a consequence of the variety of our genomes، if a mutation be present on the maternal X chromosome، then the paternal X chromosome is unlikely to also involve that. Therefore heterozygout female، due to X inactivation، only half the cells will represent this mutation. In contrast، males with identical mutation on their maternal X chromosome represent this mutation in 100% of their cells، because they only have the X chromosome from their mother. In the general population X inactivation pattern is normally dispersed; 10–20% of females have a skewed XCI model >80:20%. X-linked genes may play a role in higher sex ratio through uncommon skewing of XCI. X chromosome skewness has been reported in female carriers of neurological disorders such as X-linked mental retardation، adrenoleukodystrophy، autism and Rett syndrome. We focused here on recent comprehension of X chromosome skewness role in neurodevelopmental disorderand how Such conceptions will give guidance for different therapy.