Family matters in autism outcomes
Cognition is influenced by siblings, researchers find. Autistic children with autistic siblings have better cognition than those who are the only family member with the condition, researchers have found. Importantly, the outcome does not depend on birth order.
Although previous studies have identified that having autistic siblings leads to better cognition for individual children with the condition, it was assumed that the order in which the children were born was a significant factor.
''To date it has been thought that second-born autistic children would have better cognition because the parents already have experience and adapt their approach accordingly,'' says Dr. Lauren Lawson from La Trobe University's Olga Tennison Autism Research Centre.
New research from Dr. Lawson and her team, however, has shown that even first-born autistic children with younger autistic siblings do better than those without affected relatives.
"This is an exciting finding, because it adds to the growing consensus that there are distinct subtypes of autism," she says.
Autism Spectrum Disorder affects as much as 2% of the population, but has several variants. It can occur in only one child among siblings, or in all, or most, of them.
Understanding why this arises has long been a key research target for scientists.
''Examining differences between these families is crucial because most of our knowledge regarding the development of autism in the first years of life is based on families with multiple autistic children,'' says Dr. Lawson.
''These families only comprise only one fifth of the autism population, calling into question the validity of this knowledge for the majority of autistic individuals.''
Cheryl Dissanayake et al. Cognitive and behavioral differences in toddlers with autism spectrum disorder from multiplex and simplex families, Autism Research (2019). DOI: 10.1002/aur.2074