A quarterly publication of the Autism Research Institute

The Autism Research Review International is quarterly publication of the Autism Research Institute

Fall, 2016 | Number 4, Volume 30

Study finds that sibling ‘cross-disorder’ risk is raised for ASD, epilepsy

The risk of developing epilepsy is elevated in younger siblings of children with ASD, a new study reports, and the risk of ASD is elevated if an older sibling has epilepsy. 

Jakob Christensen and colleagues analyzed data on all children born in Denmark between 1980 and 2006 who were followed through the end of 2012. Overall, their data included more than 1.6 million children. They report that: 

• The overall adjusted hazard ratio (aHR) of epilepsy in younger siblings increased by 70% if an older sibling had ASD. 

• The overall aHR of ASD increased by 54% if an older sibling had epilepsy. 

• The risk of developing ASD or epilepsy was highest for children whose older siblings had both disorders. 

“Cross-disorder” risks were elevated for half-siblings as well as full siblings. However, the researchers say, the numbers of half-siblings were small, and this finding should be interpreted with caution. 

The researchers say, “The cross-disorder sibling risk of epilepsy and ASD was increased for the two disorders, which suggests that genes or environmental factors shared by family members may play a causal role in the co-occurrence of ASD and epilepsy.” 

In addition, they say, “For children with epilepsy and their siblings, it is important to impose clinical surveillance for ASD—especially in families in which the older sibling has both epilepsy and ASD. A similar surveillance should be imposed in relation to ASD—and again in particular if the older sibling has both ASD and epilepsy.”


“Risk of epilepsy and autism in full and half-siblings—a population-based cohort study,” Jakob Christensen, Morten Overgaard, Erik T. Parner, Mogens Vestergaard, and Dana Schendel, Epilepsia, November 8, 2016 (epub prior to print publication). Address: Jakob Christensen, Department of Neurology, Aarhus University Hospital, Norrebrogade 44, DK-8000 Aarhus C, Denmark, [email protected].