title: A genetic study of autism in Costa Rica: multiple variables affecting IQ scores observed in a preliminary sample of autistic cases.
abstract: BACKGROUND
  Autism is a heritable developmental disorder of communication and socialization that has not been well studied in Hispanic populations. Therefore, we are collecting and evaluating all possible cases of autism from a population isolate in the Central Valley of Costa Rica (CVCR) for a clinical and genetic study.
  
  
  METHODS
  We are assessing all subjects and parents, as appropriate, using the newly translated Spanish versions of the Autism Diagnostic Interview-Revised (ADI-R) and the Autism Diagnostic Observation Schedule (ADOS) as well as tests of intelligence and adaptive behavior. Detailed obstetric and family medical/psychiatric histories are taken. All cases are tested for Fragile X and will be extensively evaluated for cytogenetic abnormalities.
  
  
  RESULTS
  To date we have obtained clinical evaluations on over 76 cases of possible autism referred to our study and report data for the initial 35 complete cases. The mean age of the probands is 6.7 years, and 31 of the 35 cases are male. Twenty-one of the cases have IQs <50 and only 6 cases have IQs > or = 70. Over half of the mothers had complications during pregnancy and/or delivery. No cases have tested positively for Fragile X or PKU. Chromosomal G-banding is not yet complete for all cases.
  
  
  CONCLUSIONS
  Diagnostic data gathered on cases of autism in the CVCR using Spanish versions of the ADI-R and ADOS look similar to that generated by studies of English-speaking cases. However, only 17% of our cases have IQs within the normal range, compared to the figure of 25% seen in most studies. This result reflects an ascertainment bias in that only severe cases of autism come to treatment in the CVCR because there are no government-sponsored support programs or early intervention programs providing an incentive to diagnose autism. The severity of mental retardation seen in most of our cases may also be exaggerated by the lack of early intervention programs and the use of IQ tests without Costa Rican norms. Still, we must formally train healthcare providers and teachers to recognize and refer autistic cases with normal or near normal IQs that are not seen in treatment.
authors.affiliation: Mount Sinai School of Medicine, New York, New York, USA. alison.mcinnes@mssm.edu
authors.forename: L Alison
authors.initials: LA
authors.lastname: McInnes
authors.forename: Patricia Jiménez
authors.initials: PJ
authors.lastname: González
authors.forename: Elina R
authors.initials: ER
authors.lastname: Manghi
authors.forename: Marcela
authors.initials: M
authors.lastname: Esquivel
authors.forename: Silvia
authors.initials: S
authors.lastname: Monge
authors.forename: Marietha Fallas
authors.initials: MF
authors.lastname: Delgado
authors.forename: Eduardo
authors.initials: E
authors.lastname: Fournier
authors.forename: Pamela
authors.initials: P
authors.lastname: Bondy
authors.forename: Kathryn
authors.initials: K
authors.lastname: Castelle
mesh_terms: D000328:Adult; D001321:Autistic Disorder / Q000175:diagnosis* / Q000453:epidemiology / Q000235:genetics*; D002648:Child; D015897:Comorbidity; D003364:Costa Rica / Q000453:epidemiology; D005260:Female; D005600:Fragile X Syndrome / Q000175:diagnosis / Q000453:epidemiology; D006801:Humans; D008607:Intellectual Disability / Q000175:diagnosis / Q000453:epidemiology; D007361:Intelligence Tests / Q000706:statistics & numerical data*; D008297:Male; D008507:Medically Underserved Area; D010661:Phenylketonurias / Q000175:diagnosis / Q000453:epidemiology; D011247:Pregnancy; D011248:Pregnancy Complications / Q000453:epidemiology; D011569:Psychiatric Status Rating Scales / Q000706:statistics & numerical data; D011594:Psychometrics; D014177:Translations