title: [Mental retardation].
abstract: OBJECTIVE
  This paper describes recent advances in the neurobiology of mental retardation, emphasizing new diagnostic resources provided by cytogenetics, molecular testing, and neuroimaging.
  
  
  METHODS
  MEDLINE (January 2000 through October 2003), using the following key words: mental retardation, developmental disability, child, and adolescent. Search of the Pediatrics and New England Journal of Medicine websites using the key word mental retardation. The Online Mendelian Inheritance in Man (OMIM) database was searched for information on clinical genetics.
  
  
  RESULTS
  In October 2003, the number of genetic syndromes associated with mental retardation reached 1,149. Considering the genetic or environmental and congenital or acquired causes of mental retardation, current diagnostic investigation is able to detect the etiology in 50 to 70% of cases.
  
  
  CONCLUSIONS
  Diagnostic evaluation should follow a stepwise approach in order to make rational use of the expensive tools of cytogenetics, molecular biology, and neuroimaging.
authors.affiliation: Hospital Universitário Antônio Pedro, Universidade Federal Fluminense, Rio de Janeiro. mmvascon@centroin.com.br
authors.forename: Marcio M
authors.initials: MM
authors.lastname: Vasconcelos
mesh_terms: D000293:Adolescent; D002648:Child; D019066:Facies; D005260:Female; D006801:Humans; D008607:Intellectual Disability / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology; D008297:Male