title: [Concordance between a head circumference growth function and intellectual disability in relation with the cause of microcephaly].
abstract: BACKGROUND
  Our aim was to investigate the correlations between patterns of head growth and intellectual disability among distinct aetiological presentations of microcephaly.
  
  
  METHODS
  3,269 head circumference (HC) charts of patients from a tertiary neuropediatric unit were reviewed and 136 microcephalic participants selected. Using the Z-scores of registered HC measurements we defined the variables: HC Minimum, HC Drop and HC Catch-up. We classified patients according to the presence or absence of intellectual disability (IQ below 71) and according to the cause of microcephaly (idiopathic, familial, syndromic, symptomatic and mixed).
  
  
  RESULTS
  Using Discriminant Analysis a C-function was defined as C=HC Minimum + HC Drop with a cut-off level of C=-4.32 Z-score. In our sample 95% of patients scoring below this level, severe microcephaly, were classified in the disabled group while the overall concordance was 66%. In the symptomatic-mixed group the concordance between HC function and outcome reached 82% in contrast to only 54% in the idiopathic-syndromic group (P-value=0.0002).
  
  
  CONCLUSIONS
  We defined a HC growth function which discriminates intellectual disability of microcephalic patients better than isolated HC measurements, especially for those with secondary and mixed aetiologies.
authors.affiliation: Departament de Pediatria d'Obstetrícia i Ginecologia i de Medicina Preventiva, Universitat Autònoma de Barcelona, Bellaterra, Barcelona, España; Unitat de Neurologia Pediàtrica, Hospital de Terrassa, Terrassa, Barcelona, España. Electronic address: rcoronado@comb.cat.
authors.forename: R
authors.initials: R
authors.lastname: Coronado
authors.affiliation: Secció de Neurologia Infantil, Hospital Vall d'Hebron, Universitat Autònoma de Barcelona, Barcelona, España.
authors.forename: A
authors.initials: A
authors.lastname: Macaya Ruíz
authors.affiliation: Laboratory of Molecular Neuropharmacology and Bioinformatics, Institut de Neurociències i Unitat de Bioestadística, Universitat Autònoma de Barcelona, Barcelona, España.
authors.forename: J
authors.initials: J
authors.lastname: Giraldo Arjonilla
authors.affiliation: Secció de Neurologia Infantil, Hospital Vall d'Hebron, Universitat Autònoma de Barcelona, Barcelona, España.
authors.forename: M
authors.initials: M
authors.lastname: Roig-Quilis
mesh_terms: D002508:Cephalometry; D002675:Child, Preschool; D005260:Female; D006257:Head / Q000254:growth & development*; D006801:Humans; D007223:Infant; D008607:Intellectual Disability / Q000209:etiology*; D008297:Male; D008831:Microcephaly / Q000150:complications* / Q000209:etiology* / Q000503:physiopathology; D012189:Retrospective Studies
keywords: Análisis discriminante; Child development; Crecimiento; Desarrollo infantil; Discapacidad intelectual; Discriminant analysis; Growth; Intellectual disability; Microcefalia; Microcephaly