What genetic factors have been linked to autism spectrum disorder?

Research indicates that autism spectrum disorder (ASD) is influenced by a complex interplay of genetic and environmental factors. While the exact causes remain unclear, genetic vulnerability is a significant contributor, though its expression can differ between males and females; research suggests that females may require more mutations than males to develop the condition, supporting the "female protective model".1

Specific genetic factors linked to ASD include:

• Chromosomal Variations: Studies have identified that deletions or duplications in a region on chromosome 15 are present in some individuals with autism. Variations in this area are also associated with other neurobiological conditions, such as epilepsy.1
• Gene Variants: Variations in the CNTNAP2 gene, which facilitates neuronal connectivity in the frontal lobe, have been linked to structural and functional differences in the brain that may contribute to behavioral symptoms.2
• Neurotransmitter-Related Genes: Research into the serotonin system has highlighted the CELF6 gene; mutations in this gene have been linked to communication and learning deficits in experimental models.2

Genetic susceptibility is often studied through twin and sibling research, which helps partition phenotypic variation into genetic and environmental components.13