The KE family is a medical name designated for a British family, about half of whom exhibit a severe speech disorder called developmental verbal dyspraxia. It is the first family with speech disorder to be investigated using genetic analyses, by which the speech impairment is discovered to be due to genetic mutation, and from which the gene FOXP2, often dubbed the "language gene", was discovered. Their condition is also the first human speech and language disorder known to exhibit strict Mendelian inheritance.
Brought to medical attention from their school children in the late 1980s, the case of KE family was taken up at the UCL Institute of Child Health in London in 1990. Initial report suggested that the family was affected by a genetic disorder. Canadian linguist Myrna Gopnik suggested that the disorder was characterized primarily by grammatical deficiency, supporting the controversial notion of a "grammar gene". Geneticists at the University of Oxford determined that the condition was indeed genetic, with complex physical and physiological effects, and in 1998, they identified the actual gene, eventually named FOXP2. Contrary to the grammar gene notion, FOXP2 does not control any specific grammar or language output. This discovery directly led to a broader knowledge on human evolution as the gene is directly implicated with the origin of language.
Two family members, a boy and a girl, were featured in the National Geographic documentary film Human Ape.
Background and identity
The individual identity of the KE family are kept confidential. The family children attended Elizabeth Augur's special educational needs unit at the Lionel Primary School in Brentford, West London. Towards the end of 1980s, seven children of the family attended there. Augur began to learn that the family had a speech disorder for three generations. Of the 30 members, half of them had severe disability, some are affected mildly, and few are unaffected. Their faces show rigidity at the lower half, and most cannot complete pronouncing a word. Many of them have severe stuttering and with limited vocabulary. In particular, they have difficulty with consonants, and omit them, such as "boon" for "spoon", "able" for "table", and "bu" for "blue". Linguistic deficiency is also noted in written language both in reading and writing. They are characterized by lower nonverbal IQ.
Ethnicity
When the first study on KE family was published in 1990, the exact identity of the family was withheld and simply indicated as living in West London. The first genetic study reported in 1995 revealed that they were 30 members of four generations, with the designation "KE family." In 2009, American psychologist Elena L. Grigorenko of Yale University wrote a review paper on the genetics of developmental disorders in which she specifically described a case of speech disorder in a "three-generation pedigree of Pakistani origin from the United Kingdom (referred to as KE)." When a team of researchers from Germany, led by Arndt Wilcke of the Leipzig University, reported in 2011 the effects of FOXP2 mutation in the brain, they mentioned the family as "a large Pakistani family with severe speech and language disorder."
The British-Pakistani description for the family became widely used. However, British geneticist and neuroscientist Simon E. Fisher at the Max Planck Institute for Psycholinguistics pointed out the error in Wilcke's paper to which the German team published a corrigendum that KE family were not of Pakistani descent, but "a large English Caucasian family."