title: Behavioral genetic approach to the study of dyslexia.
abstract: OBJECTIVE
  Dyslexia is a prominent focus of practitioners, educators, and researchers because of the myriad consequences of failing to read proficiently. The aim of this study was to provide a brief overview of how twin studies can offer insight on the cause of many human behaviors and disorders including dyslexia, discuss common misconceptions regarding findings from behavioral genetic studies, briefly review the evidence on the relationship between genes, environment, and dyslexia, and finally present some findings from a large-scale twin study on reading and dyslexia.
  
  
  METHODS
  Participants were twins from a large ethnically and socioeconomically diverse twin sample in an ongoing longitudinal study of reading and dyslexia. Heritabilities of reading ability and dyslexia were calculated for 1,024 first grade twins on a standardized reading measure. Children were identified as dyslexic if they scored at the 15th percentile or below on a reading measure.
  
  
  RESULTS
  Relatively high heritabilities were observed for both reading ability and dyslexia indicating substantial genetic influences. Further, results indicated some overlap of genetic factors influencing reading ability and dyslexia.
  
  
  CONCLUSIONS
  Behavioral genetic studies offer a means of understanding the cause of dyslexia. This study extended research to a more diverse sample than extant studies and found lower heritability estimates of reading ability and dyslexia, but a similar pattern of results indicating possible genetic overlap. Twin studies provide perspective for discoveries of specific genes involved in dyslexia by quantifying the amount of variance waiting to be accounted for by genes while simultaneously providing an impetus to continue working on efforts for environmental intervention.
authors.affiliation: Department of Psychology, Florida State University, Tallahassee, FL, USA. bsodenhensler@psy.fsu.edu
authors.forename: Brooke Soden
authors.initials: BS
authors.lastname: Hensler
authors.forename: Christopher
authors.initials: C
authors.lastname: Schatschneider
authors.forename: Jeanette
authors.initials: J
authors.lastname: Taylor
authors.forename: Richard K
authors.initials: RK
authors.lastname: Wagner
mesh_terms: D000293:Adolescent; D002648:Child; D002652:Child Behavior / Q000523:psychology*; D004200:Diseases in Twins / Q000453:epidemiology / Q000235:genetics* / Q000523:psychology; D004410:Dyslexia / Q000453:epidemiology / Q000235:genetics* / Q000523:psychology*; D005260:Female; D005431:Florida / Q000453:epidemiology; D020022:Genetic Predisposition to Disease; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D011932:Reading; D012307:Risk Factors; D012931:Social Environment; D011795:Surveys and Questionnaires; D014427:Twins / Q000235:genetics* / Q000523:psychology*; D014429:Twins, Dizygotic / Q000235:genetics / Q000523:psychology; D014430:Twins, Monozygotic / Q000235:genetics / Q000523:psychology
references.citation: Curr Dir Psychol Sci. 2010 Aug 1;18(4):217-220
references.pmid: 20625474
references.citation: Acta Genet Med Gemellol (Roma). 1988;37(3-4):205-16
references.pmid: 3254013
references.citation: Nat Neurosci. 2001 Jul;4(7):752-8
references.pmid: 11426233
references.citation: Neurosci Lett. 2000 Aug 18;290(1):61-5
references.pmid: 10925175
references.citation: J Child Psychol Psychiatry. 2005 Apr;46(4):373-84
references.pmid: 15819646
references.citation: Dyslexia. 2006 Feb;12(1):21-9
references.pmid: 16512171
references.citation: Psychol Sci. 2003 Nov;14(6):623-8
references.pmid: 14629696
references.citation: Int J Legal Med. 2008 Jul;122(4):315-21
references.pmid: 18478247
references.citation: Behav Genet. 2007 Mar;37(2):273-83
references.pmid: 16977503
references.citation: Twin Res Hum Genet. 2007 Jun;10(3):434-9
references.pmid: 17564501
references.citation: J Med Genet. 2004 Feb;41(2):e19
references.pmid: 14757869
references.citation: Psychol Bull. 2005 Jul;131(4):592-617
references.pmid: 16060804
references.citation: J Learn Disabil. 1995 Feb;28(2):96-106
references.pmid: 7884303
references.citation: J Neurolinguistics. 2009 May;22(3):219-236
references.pmid: 20161176
references.citation: J Commun Disord. 2008 Sep-Oct;41(5):397-408
references.pmid: 18538338
references.citation: Science. 2009 Jul 17;325(5938):280-3
references.pmid: 19608907
references.citation: Acta Genet Med Gemellol (Roma). 1990;39(1):35-70
references.pmid: 2392892
references.citation: Read Writ. 2007 Feb 1;20(1-2):127-146
references.pmid: 19829751
references.citation: J Learn Disabil. 2006 Jan-Feb;39(1):48-55
references.pmid: 16512082
references.citation: N Engl J Med. 1992 Jan 16;326(3):145-50
references.pmid: 1727544
references.citation: J Exp Child Psychol. 2003 Feb;84(2):97-123
references.pmid: 12609495
references.citation: J Learn Disabil. 1998 May-Jun;31(3):212-33
references.pmid: 9599955
references.citation: J Child Psychol Psychiatry. 1987 Mar;28(2):229-47
references.pmid: 3584294
references.citation: Br J Educ Psychol. 2003 Mar;73(Pt 1):3-14
references.pmid: 12639274
references.citation: Arch Oral Biol. 2009 Dec;54 Suppl 1:S45-51
references.pmid: 18715551
references.citation: Schizophr Bull. 1992;18(2):171-6
references.pmid: 1621065
references.citation: Am J Med Genet C Semin Med Genet. 2009 May 15;151C(2):136-41
references.pmid: 19378334
references.citation: J Child Psychol Psychiatry. 2004 Jan;45(1):2-40
references.pmid: 14959801
references.citation: Behav Genet. 1985 Sep;15(5):467-73
references.pmid: 4074272
references.citation: Dev Neuropsychol. 2001;20(2):483-507
references.pmid: 11892949