the X-chromosome are more likely to have sex-specific expression compared to genes on the autosomes [14, 15], which results from X-inactivation in females. However, the copy of the X-chromosome that is inactivated differs within each cell and some genes (~15%) on the second X-chromosome avoid X-inactivation altogether, which can lead to increased expression of the X-linked gene(s) in females compared to males [15]. Further, X-linked genes are all fully expressed in males, making them more likely than females to be influenced by X-linked genetic variations.
