ASH1L

Autism spectrum disorder

At least seven ASH1L gene mutations have been identified in people with autism spectrum disorder (ASD), a varied condition characterized by impaired social skills, communication problems, and repetitive behaviors. Some ASH1L gene mutations associated with ASD change one building block (amino acid) in the lysine-specific methyltransferase 2H enzyme. Others delete genetic material in the ASH1L gene sequence or result in a premature stop signal that leads to an abnormally short enzyme. As a result of these mutations, the enzyme is nonfunctional. A lack of functional lysine-specific methyltransferase 2H enzyme disrupts histone methylation. The resulting changes in the expression of genes regulated by lysine-specific methyltransferase 2H affect brain development and increase the risk of ASD. Normal variations in other genes, as well as environmental risk factors, such as parental age, birth complications, and others that have not been identified, also affect an individual's risk of developing this complex condition.