Autism disorder in females is usually caused by the X chromosome inherited from their father. It affects a person’s behavior, communication, and social interaction. It can be diagnosed at any stage, but these symptoms usually start appearing during childhood. A recent study conducted on mice has revealed how inactivation of X chromosomes inherited from their father in female child can protect them from the risk of autism disorder.
A female child inherits two X chromosomes, one from each parent. But as cells need only one chromosome, they inactivate one chromosome in the embryonic development stage. This process is known as X chromosome inactivation. This process creates a mix of cells, some with an active X chromosome from the mother and some from the father. Previously, it was considered that the ratio of cells with active X chromosomes from the mother and father is 1:1. But the results of this study show that cells that inactivated X chromosomes are inherited from the father more often than the mother. This process is very important as some mutations on the X chromosome can cause autism disorder. When these mutations are inherited from the father, this partial X chromosome inactivation can help reduce the risk of autism in females.
In this study, researchers introduced a harmful mutation for Fragile X syndrome into mice to check its effect. This syndrome is a common cause of intellectual disability. Mice with the mutation from the mother showed symptoms such as anxiety and memory problems that are seen in Fragile X syndrome. On the other hand, mice with the mutation from the father did not show these issues.
The researchers of this study explain that the X chromosome is very important for the development of the brain and carries many genes that are linked to autism and other disorders. The study suggests that this partial X chromosome inactivation can protect girls from autism disorder later in life.
Reference Link:
Eric R. Szelenyi et al, Distributed X chromosome inactivation in brain circuitry is associated with X-linked disease penetrance of behavior, Cell Reports (2024).
DOI: 10.1016/j.celrep.2024.114068
