title: Motor sequencing deficit as an endophenotype of speech sound disorder:  a genome-wide linkage analysis in a multigenerational family.
abstract: OBJECTIVE
  The aim of this pilot study was to investigate a measure of motor sequencing deficit as a potential endophenotype of speech sound disorder (SSD) in a multigenerational family with evidence of familial SSD.
  
  
  METHODS
  In a multigenerational family with evidence of a familial motor-based SSD, affectation status and a measure of motor sequencing during oral motor testing were obtained. To further investigate the role of motor sequencing as an endophenotype for genetic studies, parametric and nonparametric linkage analyses were carried out using a genome-wide panel of 404 microsatellites.
  
  
  RESULTS
  In seven of the 10 family members with available data, SSD affectation status and motor sequencing status coincided. Linkage analysis revealed four regions of interest, 6p21, 7q32, 7q36, and 8q24, primarily identified with the measure of motor sequencing ability. The 6p21 region overlaps with a locus implicated in rapid alternating naming in a recent genome-wide dyslexia linkage study. The 7q32 locus contains a locus implicated in dyslexia. The 7q36 locus borders on a gene known to affect the component traits of language impairment.
  
  
  CONCLUSIONS
  The results are consistent with a motor-based endophenotype of SSD that would be informative for genetic studies. The linkage results in this first genome-wide study in a multigenerational family with SSD warrant follow-up in additional families and with fine mapping or next-generation approaches to gene identification.
authors.affiliation: Department of Speech and Hearing Sciences, University of Washington, Seattle, Washington 98195, USA. bvpeter@u.washington.edu
authors.forename: Beate
authors.initials: B
authors.lastname: Peter
authors.forename: Mark
authors.initials: M
authors.lastname: Matsushita
authors.forename: Wendy H
authors.initials: WH
authors.lastname: Raskind
mesh_terms: D002648:Child; D002675:Child, Preschool; D058068:Endophenotypes; D005191:Family Characteristics; D005260:Female; D008040:Genetic Linkage; D020022:Genetic Predisposition to Disease; D055106:Genome-Wide Association Study; D006801:Humans; D007806:Language Disorders / Q000235:genetics*; D008126:Lod Score; D008297:Male; D010375:Pedigree; D066229:Speech Sound Disorder