Brain volume findings in 6-month-old infants at high familial risk for autism.
OBJECTIVE
Individuals with autism as young as 2 years have been observed to have larger brains than healthy comparison subjects. Studies using head circumference suggest that brain enlargement is a postnatal event that occurs around the latter part of the first year. To the authors' knowledge, no previous brain imaging studies have systematically examined the period prior to age 2. In this study they used magnetic resonance imaging (MRI) to measure brain volume in 6-month-olds at high familial risk for autism.


METHODS
The Infant Brain Imaging Study (IBIS) is a longitudinal imaging study of infants at high risk for autism. This cross-sectional analysis compared brain volumes at 6 months of age in high-risk infants (N=98) and infants without family members with autism (N=36). MRI scans were also examined for radiologic abnormalities


RESULTS
No group differences were observed for intracranial, cerebrum, cerebellum, or lateral ventricle volume or for head circumference.


CONCLUSIONS
The authors did not observe significant group differences for head circumference, brain volume, or abnormalities in radiologic findings from a group of 6-month-old infants at high risk for autism. The authors are unable to conclude that these abnormalities are not present in infants who later go on to receive a diagnosis of autism; rather, abnormalities were not detected in a large group at high familial risk. Future longitudinal studies of the IBIS study group will examine whether brain volume differs in infants who go on to develop autism.
Carolina Institute for Developmental Disabilities and the Department of Psychiatry, University of North Carolina, Chapel Hill, USA. hcody@med.unc.edu
Heather Cody
HC
Hazlett
Hongbin
H
Gu
Robert C
RC
McKinstry
Dennis W W
DW
Shaw
Kelly N
KN
Botteron
Stephen R
SR
Dager
Martin
M
Styner
Clement
C
Vachet
Guido
G
Gerig
Sarah J
SJ
Paterson
Robert T
RT
Schultz
Annette M
AM
Estes
Alan C
AC
Evans
Joseph
J
Piven
D001321:Autistic Disorder / Q000473:pathology*; D001921:Brain / Q000254:growth & development / Q000473:pathology*; D016022:Case-Control Studies; D002531:Cerebellum / Q000473:pathology; D002552:Cerebral Ventricles / Q000473:pathology; D054022:Cerebrum / Q000473:pathology; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005260:Female; D006257:Head / Q000473:pathology; D006801:Humans; D007223:Infant; D008279:Magnetic Resonance Imaging; D008297:Male; D059906:Neuroimaging; D009929:Organ Size