what type of mutation is fragile x syndrome
Fragile X syndrome Fragile X syndrome co-occurs with autism in many cases and is a suspected genetic cause of the autism in these cases.[8][15] This finding has resulted in screening for FMR1 mutation to be considered mandatory in children diagnosed with autism.[8] Of those with fragile X syndrome, prevalence of concurrent autism spectrum disorder (ASD) has been estimated to be between 15 and 60%, with the variation due to differences in diagnostic methods and the high frequency of autistic features in individuals with fragile X syndrome not meeting the DSM criteria for an ASD.[15]
XY sex-determination system In humans, half of spermatozoons carry X chromosome and the other half Y chromosome.[3] A single gene (SRY) present on the Y chromosome acts as a signal to set the developmental pathway towards maleness. Presence of this gene starts off the process of virilization. This and other factors result in the sex differences in humans.[4] The cells in females, with two X chromosomes, undergo X-inactivation, in which one of the two X chromosomes is inactivated. The inactivated X chromosome remains within a cell as a Barr body.