Question What are the etiological origins of autism spectrum disorder?
Findings In a large population-based multinational cohort study including more than 2 million individuals, 22 156 of whom were diagnosed with ASD, the heritability of autism spectrum disorder was estimated to be approximately 80%, with possible modest differences in the sources of autism spectrum disorder risk replicated across countries.
Meaning The variation in the occurrence of autism spectrum disorder in the population is mostly owing to inherited genetic influences, with no support for contribution from maternal effects.
Importance The origins and development of autism spectrum disorder (ASD) remain unresolved. No individual-level study has provided estimates of additive genetic, maternal, and environmental effects in ASD across several countries.
Objective To estimate the additive genetic, maternal, and environmental effects in ASD.
Design, Setting, and Participants Population-based, multinational cohort study including full birth cohorts of children from Denmark, Finland, Sweden, Israel, and Western Australia born between January 1, 1998, and December 31, 2011, and followed up to age 16 years. Data were analyzed from September 23, 2016 through February 4, 2018.
Main Outcomes and Measures Across 5 countries, models were fitted to estimate variance components describing the total variance in risk for ASD occurrence owing to additive genetics, maternal, and shared and nonshared environmental effects.
Results The analytic sample included 2 001 631 individuals, of whom 1 027 546 (51.3%) were male. Among the entire sample, 22 156 were diagnosed with ASD. The median (95% CI) ASD heritability was 80.8% (73.2%-85.5%) for country-specific point estimates, ranging from 50.9% (25.1%-75.6%) (Finland) to 86.8% (69.8%-100.0%) (Israel). For the Nordic countries combined, heritability estimates ranged from 81.2% (73.9%-85.3%) to 82.7% (79.1%-86.0%). Maternal effect was estimated to range from 0.4% to 1.6%. Estimates of genetic, maternal, and environmental effects for autistic disorder were similar with ASD.
Conclusions and Relevance Based on population data from 5 countries, the heritability of ASD was estimated to be approximately 80%, indicating that the variation in ASD occurrence in the population is mostly owing to inherited genetic influences, with no support for contribution from maternal effects. The results suggest possible modest differences in the sources of ASD risk between countries.
JoeyCalamaro on July 18th, 2019 at 20:55 UTC »
I have a child diagnosed with autism and, during the diagnostic process, I suggested that a lot of her quirks could simply be related to her personality. We're a lot a like and I struggled with many of the same issues as a child, albeit not in such a pronounced way.
After explaining all this to the psychologist, she suggested something that really threw me for a loop — maybe I had autism too and was just never diagnosed. It was certainly a humbling moment for me but I didn't think too much about it until a second psychologist suggested the same thing.
I never followed through with a diagnosis, or anything like that. I feel that I function just fine and I'm not sure how productive a clinical diagnosis would even be at this stage of my life. But it certainly made me reconsider a lot about my own experiences growing up, that's for sure.
dunzoes on July 18th, 2019 at 18:53 UTC »
If my brother had it what are the chances I'd have of passing it ? Edit: study purely tracked parents on the spectrum. Still curious if theres a correlation with siblings
BoinkBoinkEtAliae on July 18th, 2019 at 16:19 UTC »
This research also seems to indicate it's passed down through both parents, instead of the prevailing theory that it's mostly maternal.
Autism is also habitually underdiagnosed in women.