The KE family is an extended family, about half of whom exhibit Developmental Verbal Dyspraxia (DVD). The genetic trace across many individuals spanning three generations of the family has been the subject of intense worldwide research since 1990, when Myrna Gopnik reported on them concerning the genetic origin of language. In the scientific literature, the family is usually identified as the KE family (sometimes the K family), and as living in London. Of the 30 members across three generations, about half suffer from severe deficiency, and the other half are unaffected to various degrees.
The deficiencies reported are that impaired family members "have trouble controlling fine movements in the lower half of their face, and this gives them problems when making the complicated sounds necessary for speech". However, they also have difficulty writing down "as many words as they can think of beginning with a particular letter", which indicates that the pathologies are more profound than that of speech alone.
Clearly the source of this deficit is inherited, which is why the family has been the subject of such interest among geneticists.
In 1998, Simon Fisher and colleagues identified a small section of chromosome 7, dubbed SPCH1, which was linked to the speech and language disorder in this family. The team went on to discover a particular mutation (a missense mutation) affecting a specific nucleotide of the FOXP2 gene in this chromosomal region. Not only did this differ between the speech-impaired and unaffected members of the KE family, but the same gene was also found to be affected by a different type of mutation (a chromosomal translocation) in another unrelated individual with similar deficiencies.
The specific identity of the family does not appear to be publicly known.
- Apraxia of speech
- Developmental coordination disorder
- Evolutionary linguistics
- FOXP2 and human evolution
- Belton E, Salmond CH, Watkins KE, Vargha-Khadem F, Gadian DG (March 2003). "Bilateral brain abnormalities associated with dominantly inherited verbal and orofacial dyspraxia". Hum Brain Mapp 18 (3): 194–200. doi:10.1002/hbm.10093. PMID 12599277.
- Gopnik M (April 1990). "Feature-blind grammar and dysphagia". Nature 344 (6268): 715. doi:10.1038/344715a0. PMID 2330028.
- MacWhinney, Brian (2002). "Language Emergence". An integrated view of language development - Papers in honor of Henning Wode (Trier: Wissenschaftlicher Verlag): 17–42. Retrieved 2006-03-26.
- Preuss TM (June 2012). "Human brain evolution: from gene discovery to phenotype discovery". Proc. Natl. Acad. Sci. U.S.A. 109 Suppl 1: 10709–16. doi:10.1073/pnas.1201894109. PMC 3386880. PMID 22723367.
- Bijal P. Trivedi (2001-10-04). "Scientists Identify a Language Gene". National Geographic Today. Retrieved 2008-03-26.
- Vargha-Khadem, Faraneh; Liegeois, Frederique (2007). "From speech to gene: The KE family and the FOXP2". In Stein Braten. On Being Moved : From Mirror Neurons to Empathy (Amsterdam: John Benjamins Publishing Company). pp. 137–146. ISBN 9789027252043. OCLC 643718628.
- Vargha-Khadem F, Watkins K, Alcock K, Fletcher P, Passingham R (January 1995). "Praxic and nonverbal cognitive deficits in a large family with a genetically transmitted speech and language disorder". Proc. Natl. Acad. Sci. U.S.A. 92 (3): 930–3. doi:10.1073/pnas.92.3.930. PMC 42734. PMID 7846081.
- Watkins KE, Gadian DG, Vargha-Khadem F (November 1999). "Functional and structural brain abnormalities associated with a genetic disorder of speech and language". Am. J. Hum. Genet. 65 (5): 1215–21. doi:10.1086/302631. PMC 1288272. PMID 10521285.
- Fisher SE, Vargha-Khadem F, Watkins KE, Monaco AP, Pembrey ME (February 1998). "Localisation of a gene implicated in a severe speech and language disorder". Nat. Genet. 18 (2): 168–70. doi:10.1038/ng0298-168. PMID 9462748.
- Lai CS, Fisher SE, Hurst JA, Vargha-Khadem F, Monaco AP (2001-10-04). "A forkhead-domain gene is mutated in a severe speech and language disorder". Nature 413 (6855): 519–523. doi:10.1038/35097076. PMID 11586359.
- Fisher SE, Scharff C (April 2009). "FOXP2 as a molecular window into speech and language". Trends Genet. 25 (4): 166–77. doi:10.1016/j.tig.2009.03.002. PMID 19304338.