Autism spectrum disorders and autistic traits: A decade of new twin studies

  title={Autism spectrum disorders and autistic traits: A decade of new twin studies},
  author={Angelica Ronald and Rosa A. Hoekstra},
  journal={American Journal of Medical Genetics Part B: Neuropsychiatric Genetics},
  • A. RonaldR. Hoekstra
  • Published 1 April 2011
  • Psychology
  • American Journal of Medical Genetics Part B: Neuropsychiatric Genetics
Researchers continue to pursue a better understanding of the symptoms, comorbidities, and causes of autism spectrum disorders. In this article we review more than 30 twin studies of autism spectrum disorders (ASDs) and autistic traits published in the last decade that have contributed to this endeavor. These twin studies have reported on the heritability of autism spectrum disorders and autistic traits in different populations and using different measurement and age groups. These studies have… 

Progress in Understanding the Causes of Autism Spectrum Disorders and Autistic Traits: Twin Studies from 1977 to the Present Day

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Autistic spectrum disorders: A review of clinical features, theories and diagnosis

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Autism spectrum disorders and coexisting disorders in a nationwide Swedish twin study.

Detailed phenotypic descriptions including symptoms of problems associated with a wide range of child psychiatric disorders may aid in unraveling the genetic architecture of ASD and should guide the development of intervention strategies addressing each problem type specifically.

Autism spectrum disorders and autistic traits share genetics and biology

Evidence is provided for an overlapping genetic and biological etiology underlying ASDs and autistic population traits, which suggests that genetic studies in the general population may yield novel ASD genes.

Autistic Traits Below the Clinical Threshold: Re-examining the Broader Autism Phenotype in the 21st Century

The value of further research into the Broader Autism Phenotype is reviewed, with an emphasis on deriving heritable endophenotypes which will reliably index autism susceptibility and offer neurodevelopmental mechanisms that bridge the gap between genes and a clinical autism diagnosis.

Autism spectrum disorders and autistic like traits: similar etiology in the extreme end and the normal variation.

An etiological similarity between ASDs and ALTs in the normal variation is demonstrated and, with results from previous studies, the data suggest that ASDsand ALTs are etiologically linked.

Heritability of autism spectrum disorders: a meta‐analysis of twin studies

It is demonstrated that ASD is due to strong genetic effects and shared environmental effects become significant as a function of lower prevalence rate, and previously reported significant shared environmental influences are likely a statistical artefact of overinclusion of concordant DZ twins.

Genetic research in autism spectrum disorders

Genetic studies have the potential to identify the biological underpinnings of ASDs and other neuropsychiatric disorders and are already being used to examine disease pathways and pathogenesis.

What have we learned from recent twin studies about the etiology of neurodevelopmental disorders?

The findings of twin studies implicate substantial heritability of NDDs, and warrant large-scale molecular genetic studies for such traits.

Identification of biobehavioral markers of neurodevelopmental disorders in twins

The results support that systemic preand postnatal elemental dysregulation increase ASD risk, and an association between early medical events and ASD risk is found, and point to a cumulative multifactor threshold model, including both genetic and NSE components in the etiology of ASD.



The genetics of autism spectrum disorders and related neuropsychiatric disorders in childhood.

Different neuropsychiatric disorders seem to have a common genetic etiology, suggesting caution in the use of diagnostic entities and proband status in efforts to uncover genes predisposing to autism spectrum disorders.

Genetic heterogeneity between the three components of the autism spectrum: a twin study.

The results suggest the triad of impairments that define autism spectrum disorders is heterogeneous genetically, and molecular genetic research examining the three aspects separately may identify different causal pathways for the three components.

Genetic correlation between autistic traits and IQ in a population-based sample of twins with autism spectrum disorders (ASDs)

There is a substantial overlap between the genetic factors that influence individual variation in autistic traits and IQ, irrespective of gender, and the individual life experiences that increase autistic traits have a moderate overlap with those that contribute to individual IQs.

Limited genetic covariance between autistic traits and intelligence: Findings from a longitudinal twin study

Investigation of the longitudinal association between autistic traits and intelligence in a general population twin sample and the etiology of this association suggest that individual differences in autistic traits are substantially genetically independent of intellectual functioning.

Relationship Between Symptom Domains in Autism Spectrum Disorders: A Population Based Twin Study

Findings from a clinical sample of twins indicate a fractionation of social/communicative and RRBI symptoms in ASD.

On the twin risk in autism.

The data clearly do not support twinning as a substantial risk factor in the etiology of autism, and it is demonstrated that the high proportion of twins found in affected-sib-pair studies can be adequately explained by the high ratio of concordance rates in monozygotic twins versus siblings and the distribution of family size in the population studied.

Evidence for overlapping genetic influences on autistic and ADHD behaviours in a community twin sample.

There are some common genetic influences operating across autistic traits and ADHD behaviours throughout normal variation and at the extreme, which is relevant for molecular genetic research, as well as for psychiatrists and psychologists, who may have assumed these two sets of behaviours are independent.

A twin study of autism symptoms in Sweden

It is suggested that the autism triad consists of three partly independent dimensions when assessed in the general population, and that these different autism symptoms, to a considerable extent, have partly separate genetic influences.

Autism as a strongly genetic disorder: evidence from a British twin study

The findings indicate that autism is under a high degree of genetic control and suggest the involvement of multiple genetic loci.

The factor structure of autistic traits.

Future studies of the association between genetic/neurobiologic markers and autistic symptomatology may be enhanced by approaches which consider autistic symptoms as quantitative traits, and which are informed by ongoing research on the development and phenomenology of core deficiencies in reciprocal social behavior.