KE Family

The KE family is an extended family, about half of whom exhibit severe forms of specific language impairment (SLI). The genetic trace across many individuals spanning three generations of the family has been the subject of intense worldwide research since at least 1990, 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.

Myrna Gopnik reported on them in 1990. The specific identity of the family does not appear to be publicly known.