Intergenerational transmission of subthreshold autistic traits in the general population.
BACKGROUND
Autistic disorder (AD) is a disabling oligogenic condition characterized by severe social impairment. Subthreshold autistic social impairments are known to aggregate in the family members of autistic probands; therefore, we conducted this study to examine the intergenerational transmission of such traits in the general population.


METHODS
The Social Responsiveness Scale (SRS), a quantitative measure of autistic traits, was completed on 285 pairs of twins (by maternal report) and on their parents (by spouse report).


RESULTS
Correlation for social impairment or competence between parents and their children and between spouses was on the order of .4. In families in which both parents scored in the upper quartile for social impairment on the SRS, mean SRS score of offspring was significantly elevated (effect size 1.5). Estimated assortative mating explained approximately 30% of the variation in parent SRS scores.


CONCLUSIONS
Children from families in which both parents manifest subthreshold autistic traits exhibit a substantial shift in the distribution of their scores for impairment in reciprocal social behavior, toward the pathological end. As has been previously demonstrated in children, heritable subthreshold autistic impairments are measurable in adults and appear continuously distributed in the general population.
Constantino
John N
JN
Department of Psychiatry, Washington University School of Medicine, St. Louis, MO 63110, USA. constantino@wustl.edu
Todd
Richard D
RD
D000293:Adolescent; D000328:Adult; D001321:Autistic Disorder / Q000453:epidemiology / Q000235:genetics / Q000523:psychology; D002648:Child; D002659:Child Development Disorders, Pervasive / Q000453:epidemiology / Q000235:genetics / Q000523:psychology; D039721:Diagnostic and Statistical Manual of Mental Disorders; D004200:Diseases in Twins / Q000453:epidemiology / Q000235:genetics / Q000523:psychology; D005192:Family Health; D005260:Female; D005500:Follow-Up Studies; D020022:Genetic Predisposition to Disease / Q000235:genetics; D006801:Humans; D016901:Intergenerational Relations; D007406:Interview, Psychological / Q000379:methods; D008297:Male; D016743:Mental Competency / Q000523:psychology; D008875:Middle Aged; D010287:Parent-Child Relations; D011594:Psychometrics / Q000379:methods; D012720:Severity of Illness Index; D012919:Social Behavior; D018433:Twin Studies as Topic