An extremely rare condition, showing autosomal dominant inheritance, that affects a British family (the KE family) and causes a severe language disorder. The afflicted individuals are unable to learn certain rules of grammar and tense, and they cannot enunciate certain verbal patterns. The gene involved is FOXP2, located at 7q31, and it spans approximately 600 kb of DNA. Two functional copies of FOXP2 are required for the acquisition of normal spoken language. The gene contains over 20 exons, and it spans approximately 600 kb of DNA. There are at least four mRNAs transcribed from FOXP2 by alternative splicing (q.v.), and these transcripts are plentiful in the fetal brain. The most common splice form encodes a protein 715 amino acids long. A segment of this protein contains a DNA-binding site, suggesting that it functions as a regulator of transcription. Homologs of FOXP2 have been identified in the chimpanzee, the gorilla, and the orangutan. The FOXP2 proteins of the apes are all identical to each other, but the human protein has different amino acids at two sites. Perhaps these changes gave new properties to the protein which influenced neural systems in ways that eventually led to the acquisition of speech. See Chronology, 2001, Lai et al.
Subjects: Genetics and Genomics.