title: Etiologic yield of subspecialists' evaluation of young children with global developmental delay.
abstract: OBJECTIVE
  To determine the etiologic yield of subspecialists' evaluation of young children with global developmental delay. In addition, variables that may predict finding an underlying etiology were also identified.
  
  
  METHODS
  All children <5 years of age, referred over an 18-month period to subspecialty services for initial evaluation of a suspected developmental delay, were prospectively enrolled. Diagnostic yield was ascertained after the completion of clinical assessments and laboratory investigations requested by the evaluating physician.
  
  
  RESULTS
  Ninety-nine children (71 boys) were found to have global developmental delay; 96% had a mild or moderate delay documented. An etiologic diagnosis was determined in 44. Four diagnoses (cerebral dysgenesis, hypoxic-ischemic encephalopathy, toxin exposure, chromosomal abnormalities) accounted for 34 of 44 (77%) of the diagnoses made. The presence of co-existing autistic traits was associated with significantly decreased diagnostic yield (0/19 vs 44/80, P <.0001), whereas specific historical features (eg, family history, toxin exposure, and perinatal difficulty; 23/32 vs 21/67, P =.0002) and findings on physical examination (eg, dysmorphology, microcephaly, and focal motor findings; 35/48 vs 9/51, P <.0001) were significantly associated with identifying a diagnosis. Multiple logistic regression analysis identified antenatal toxin exposure, microcephaly, focal motor findings, and the absence of autistic traits as significant predictor variables for the identification of an etiology.
  
  
  CONCLUSIONS
  An etiologic diagnosis is often possible in the young child with global developmental delay, particularly in the absence of autistic features. Etiologic yield is augmented by presence of specific findings on history or physical examination on initial assessment.
authors.affiliation: Departments of Neurology/Neurosurgery, Pediatrics, and Epidemiology and Biostatistics and School of Physical & Occupational Therapy, McGill University, Montreal, Quebec, Canada.
authors.forename: M I
authors.initials: MI
authors.lastname: Shevell
authors.forename: A
authors.initials: A
authors.lastname: Majnemer
authors.forename: P
authors.initials: P
authors.lastname: Rosenbaum
authors.forename: M
authors.initials: M
authors.lastname: Abrahamowicz
mesh_terms: D001321:Autistic Disorder / Q000175:diagnosis / Q000209:etiology; D002675:Child, Preschool; D015331:Cohort Studies; D002658:Developmental Disabilities / Q000175:diagnosis / Q000209:etiology*; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D010808:Physical Examination; D011446:Prospective Studies