What is the research about?

The family members of people with ASD often share many of their traits but don’t have the number or severity of symptoms needed to be diagnosed with the condition. This study looked at whether having multiple children or only one child with ASD, or the sex of the children with ASD in a family influenced the presence and severity of symptoms in the children without a diagnosis of ASD.


What did the researchers do?

The family members of people with ASD often share many of their traits but don’t have the number or severity of symptoms needed to be diagnosed with the condition. This study looked at whether having multiple children or only one child with ASD, or the sex of the children with ASD in a family influenced the presence and severity of symptoms in the children without a diagnosis of ASD.


What did the researchers find?

The researchers found that

  • the siblings of children with ASD were more likely to show higher levels of ASDsymptoms if they were many members of their family with ASD
  • the boys who did not have ASD were more likely to have a higher number of symptoms, as were boys with the language delay or speech patterns usually seen in children with ASD,
  • the children with ASD in families with several members with ASD had lower levels of symptoms than did the children with ASD, if they were the only child in the family with the condition,
  • the likelihood of having more than one child with ASD in a family was higher if that family had female members with ASD, and
  •  it is likely that girls need a much greater number of the genes related to ASD to produce the symptoms needed to warrant a diagnosis of ASD.

Take home message

Both the sex and the number of children with ASD in a family strongly influence the risk of their non-affected siblings having a high number of autism symptoms. The data also show that these siblings have a higher likelihood of having children with ASD. The information gained from this study could help provide counselling for non-affected siblings about their likelihood of having children with ASD.


Notes

The original Research Report was written by T.W. Frazier and colleagues and published in Molecular Autism. 2015.