title: Genetic and environmental influences on the cognitive outcomes of children with fragile X syndrome.
abstract: OBJECTIVE
  To measure the genetic and environmental factors influencing the cognitive outcomes in children with fragile X, a common genetic disorder causing cognitive impairments.
  
  
  METHODS
  In-home evaluations were conducted on 120 children (80 boys and 40 girls) with the fragile X full mutation and their unaffected siblings.
  
  
  RESULTS
  Multiple regression analyses show that the cognitive outcomes for girls with fragile X are most strongly predicted by the mean IQ of their parents, with a small proportion of the variance accounted for by the quality of their home environment. FMR1 protein (FMRP) was associated with girls' levels of distractibility. Mean parental IQ was associated only with boys' Performance IQs, while FMRP was associated with boys' Full Scale IQs. The quality of boys' home environments accounted for more of the variance in their cognitive outcomes than it did for affected girls.
  
  
  CONCLUSIONS
  Both biological/genetic factors and environmental factors are significant predictors of IQ in children with fragile X syndrome; however, the influence of specific factors differs between girls and boys. These findings lay the foundation for further investigation into biological and environmental interventions.
authors.affiliation: Department of Psychiatry, Stanford University School of Medicine, CA 94305-5719, USA. jennydf@stanford.edu
authors.forename: Jennifer
authors.initials: J
authors.lastname: Dyer-Friedman
authors.forename: Bronwyn
authors.initials: B
authors.lastname: Glaser
authors.forename: David
authors.initials: D
authors.lastname: Hessl
authors.forename: Cindy
authors.initials: C
authors.lastname: Johnston
authors.forename: Lynne C
authors.initials: LC
authors.lastname: Huffman
authors.forename: Annette
authors.initials: A
authors.lastname: Taylor
authors.forename: Jacob
authors.initials: J
authors.lastname: Wisbeck
authors.forename: Allan L
authors.initials: AL
authors.lastname: Reiss
mesh_terms: D002648:Child; D003072:Cognition Disorders / Q000175:diagnosis* / Q000453:epidemiology / Q000209:etiology; D004777:Environment; D005260:Female; D005600:Fragile X Syndrome / Q000150:complications / Q000453:epidemiology / Q000235:genetics*; D020022:Genetic Predisposition to Disease; D006801:Humans; D008297:Male; D009483:Neuropsychological Tests