title: Clinical, morphological, and biochemical correlates of head circumference in autism.
abstract: BACKGROUND
  Head growth rates are often accelerated in autism. This study is aimed at defining the clinical, morphological, and biochemical correlates of head circumference in autistic patients.
  
  
  METHODS
  Fronto-occipital head circumference was measured in 241 nonsyndromic autistic patients, 3 to 16 years old, diagnosed according to DSM-IV criteria. We assessed 1) clinical parameters using the Autism Diagnostic Observation Schedule, Autism Diagnostic Interview-Revised, Vineland Adaptive Behavioral Scales, intelligence quotient measures, and an ad hoc clinical history questionnaire; 2) height and weight; 3) serotonin (5-HT) blood levels and peptiduria.
  
  
  RESULTS
  The distribution of cranial circumference is significantly skewed toward larger head sizes (p < .00001). Macrocephaly (i.e., head circumference >97th percentile) is generally part of a broader macrosomic endophenotype, characterized by highly significant correlations between head circumference, weight, and height (p < .001). A head circumference >75th percentile is associated with more impaired adaptive behaviors and with less impairment in IQ measures and motor and verbal language development. Surprisingly, larger head sizes are significantly associated with a positive history of allergic/immune disorders both in the patient and in his/her first-degree relatives.
  
  
  CONCLUSIONS
  Our study demonstrates the existence of a macrosomic endophenotype in autism and points toward pathogenetic links with immune dysfunctions that we speculate either lead to or are associated with increased cell cycle progression and/or decreased apoptosis.
authors.affiliation: Laboratory of Molecular Psychiatry and Neurogenetics, University Campus Bio-Medico, and I.R.C.C.S. Fondazione Santa Lucia, Rome, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Sacco
authors.forename: Roberto
authors.initials: R
authors.lastname: Militerni
authors.forename: Alessandro
authors.initials: A
authors.lastname: Frolli
authors.forename: Carmela
authors.initials: C
authors.lastname: Bravaccio
authors.forename: Antonella
authors.initials: A
authors.lastname: Gritti
authors.forename: Maurizio
authors.initials: M
authors.lastname: Elia
authors.forename: Paolo
authors.initials: P
authors.lastname: Curatolo
authors.forename: Barbara
authors.initials: B
authors.lastname: Manzi
authors.forename: Simona
authors.initials: S
authors.lastname: Trillo
authors.forename: Carlo
authors.initials: C
authors.lastname: Lenti
authors.forename: Monica
authors.initials: M
authors.lastname: Saccani
authors.forename: Cindy
authors.initials: C
authors.lastname: Schneider
authors.forename: Raun
authors.initials: R
authors.lastname: Melmed
authors.forename: Karl-Ludvig
authors.initials: KL
authors.lastname: Reichelt
authors.forename: Tiziana
authors.initials: T
authors.lastname: Pascucci
authors.forename: Stefano
authors.initials: S
authors.lastname: Puglisi-Allegra
authors.forename: Antonio M
authors.initials: AM
authors.lastname: Persico
mesh_terms: D000293:Adolescent; D000367:Age Factors; D000704:Analysis of Variance; D001321:Autistic Disorder / Q000097:blood* / Q000473:pathology*; D001835:Body Weight; D002508:Cephalometry / Q000379:methods; D002648:Child; D002657:Child Development / Q000502:physiology; D002675:Child, Preschool; D019465:Craniofacial Abnormalities / Q000473:pathology; D005260:Female; D006257:Head / Q000254:growth & development* / Q000473:pathology*; D006801:Humans; D007360:Intelligence; D008297:Male; D010808:Physical Examination; D012016:Reference Values; D012044:Regression Analysis; D012701:Serotonin / Q000097:blood*
chemical_list: D012701:Serotonin