Shared familial transmission of autism spectrum and attention-deficit/hyperactivity disorders.
BACKGROUND
To determine whether familial transmission is shared between autism spectrum disorders and attention-deficit/hyperactivity disorder, we assessed the prevalence, rates of comorbidity, and familial transmission of both disorders in a large population-based sample of children during a recent 7 year period.


METHODS
Study participants included all children born to parents with the Kaiser Permanente Northwest (KPNW) Health Plan between 1 January 1998 and 31 December 2004 (n = 35,073). Children and mothers with physician-identified autism spectrum disorders (ASD) and/or attention-deficit/hyperactivity disorder (ADHD) were identified via electronic medical records maintained for all KPNW members.


RESULTS
Among children aged 6-12 years, prevalence was 2.0% for ADHD and 0.8% for ASD; within those groups, 0.2% of the full sample (19% of the ASD sample and 9.6% of the ADHD sample) had co-occurring ASD and ADHD, when all children were included. When mothers had a diagnosis of ADHD, first born offspring were at 6-fold risk of ADHD alone (OR = 5.02, p < .0001) and at 2.5-fold risk of ASD alone (OR = 2.52, p < .01). Results were not accounted for by maternal age, child gestational age, child gender, and child race.


CONCLUSIONS
Autism spectrum disorders shares familial transmission with ADHD. ADHD and ASD have a partially overlapping diathesis.
Oregon Health & Science University, Sam Jackson Park Road, Portland, OR, USA; University of Oregon, Eugene, OR, USA.
Erica D
ED
Musser
Elizabeth
E
Hawkey
Svetlana S
SS
Kachan-Liu
Paul
P
Lees
Jean-Baptiste
JB
Roullet
Katrina
K
Goddard
Robert D
RD
Steiner
Joel T
JT
Nigg
D001289:Attention Deficit Disorder with Hyperactivity / Q000453:epidemiology* / Q000235:genetics*; D002648:Child; D002659:Child Development Disorders, Pervasive / Q000453:epidemiology* / Q000235:genetics*; D015897:Comorbidity; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D008297:Male; D009035:Mothers / Q000706:statistics & numerical data*; D015205:Northwestern United States / Q000453:epidemiology; D015995:Prevalence
Attention-deficit/hyperactivity disorder; autism spectrum disorder; shared familial transmission