Evidence That Autistic Traits Show the Same Etiology in the General Population and at the Quantitative Extremes (5%, 2.5%, and 1%)

TY - JOUR

T1 - Evidence That Autistic Traits Show the Same Etiology in the General Population and at the Quantitative Extremes (5%, 2.5%, and 1%)

AU - Robinson, Elise B.

AU - Koenen, Karestan C.

AU - McCormick, Marie C.

AU - Munir, Kerim

AU - Hallett, Victoria

AU - Happe, Francesca

AU - Plomin, Robert

AU - Ronald, Angelica

PY - 2011/11

Y1 - 2011/11

N2 - Context: Genetic factors play an important role in the etiology of both autism spectrum disorders and autistic traits. However, little is known about the etiologic consistency of autistic traits across levels of severity.Objective: To compare the etiology of typical variation in autistic traits with extreme scoring groups (including top 1%) that mimicked the prevalence of diagnosed autism spectrum disorders in the largest twin study of autistic traits to date.Design: Twin study using phenotypic analysis and genetic model-fitting in the total sample and extreme scoring groups (top 5%, 2.5%, and 1%).Setting: A nationally representative twin sample from the general population of England.Participants: The families of 5968 pairs aged 12 years old in the Twins’ Early Development Study.Main Outcome Measure: Autistic traits as assessed by the Childhood Autism Spectrum Test.Results: Moderate to high heritability was found for autistic traits in the general population (53% for females and 72% for males). High heritability was found in extreme-scoring groups. There were no differences in heritability among extreme groups or between the extreme groups and the general population. A continuous liability shift toward autistic trait affectedness was seen in the cotwins of individuals scoring in the top 1%, suggesting shared etiology between extreme scores and normal variation.Conclusion: This evidence of similar etiology across normal variation and the extremes has implications for molecular genetic models of autism spectrum disorders and for conceptualizing autism spectrum disorders as the quantitative extreme of a neurodevelopmental continuum.

AB - Context: Genetic factors play an important role in the etiology of both autism spectrum disorders and autistic traits. However, little is known about the etiologic consistency of autistic traits across levels of severity.Objective: To compare the etiology of typical variation in autistic traits with extreme scoring groups (including top 1%) that mimicked the prevalence of diagnosed autism spectrum disorders in the largest twin study of autistic traits to date.Design: Twin study using phenotypic analysis and genetic model-fitting in the total sample and extreme scoring groups (top 5%, 2.5%, and 1%).Setting: A nationally representative twin sample from the general population of England.Participants: The families of 5968 pairs aged 12 years old in the Twins’ Early Development Study.Main Outcome Measure: Autistic traits as assessed by the Childhood Autism Spectrum Test.Results: Moderate to high heritability was found for autistic traits in the general population (53% for females and 72% for males). High heritability was found in extreme-scoring groups. There were no differences in heritability among extreme groups or between the extreme groups and the general population. A continuous liability shift toward autistic trait affectedness was seen in the cotwins of individuals scoring in the top 1%, suggesting shared etiology between extreme scores and normal variation.Conclusion: This evidence of similar etiology across normal variation and the extremes has implications for molecular genetic models of autism spectrum disorders and for conceptualizing autism spectrum disorders as the quantitative extreme of a neurodevelopmental continuum.

KW - MULTIPLE-REGRESSION ANALYSIS

KW - RECIPROCAL SOCIAL-BEHAVIOR

KW - CAST CHILDHOOD ASPERGER

KW - TWIN DATA

KW - INDIVIDUAL-DIFFERENCES

KW - GENETIC-RELATIONSHIP

KW - DISORDERS

KW - SPECTRUM

KW - HERITABILITY

KW - CHILDREN

U2 - 10.1001/archgenpsychiatry.2011.119

DO - 10.1001/archgenpsychiatry.2011.119

M3 - Article

SN - 0003-990X

VL - 68

SP - 1113

EP - 1121

JO - Archives of General Psychiatry

JF - Archives of General Psychiatry

IS - 11

ER -