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 normal 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, a short stretch on chromosome 7 of gene FOXP2, dubbed SPCH1, was identified as being different between the members of the family exhibiting the damage versus those who do not. Subsequently, a particular mutation affecting a specific nucleotide in the 7q31 region on this gene was found to be broken by a translocation or missense mutation. Not only did this differ between the speech-impaired and normal members of the KE family, but it was also found to be deficient in one other individual with similar deficiencies.

Research continues on the genetic history of this particular family. In 2002, it was argued that, based on the difference between the human and chimp FOXP2 genes, the language-relevant mutation may have occurred between 10,000 and 100,000 years ago. This may provide a bound on the origins of language – but this link is very tenuous.

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