[FOXP2: from the specific disorder to the molecular biology of language. I. Aetiological, neuroanatomical, neurophysiological and molecular aspects].
BACKGROUND
The task of cloning the genes whose products are involved in the organisation and functioning of the nerve centres that enable language tasks to be executed must necessarily start with the identification and the cognitive, linguistic, neuroanatomical and neurophysiological analysis of individuals with hereditary (specific) language impairment (SLI).


METHODS
The first of these genes to be characterised in this way--a gene called FOXP2--codes for a regulating factor that acts as a transcriptional repressor in the central nervous system. It is expressed in neuronal populations mainly situated in the basal ganglia, but also in the cortex, cerebellum and the thalamus, which are presumably involved in the development and/or functioning of the thalamic-cortical-striatal circuits associated with motor planning and learning. The protein FOXP2 shows several structural patterns that, when altered in other proteins, also give rise to different disorders in the central nervous system. The pattern of expression of the gene is preserved phylogenetically, although this does not happen in the case of the pattern of mRNA maturation. In individuals with a mutated version of FOXP2, morphological and functional anomalies are detected in those areas in which the gene is expressed. These abnormalities can be correlated satisfactorily with the phenotypic characteristics of the disorder, which are at the same time of both a motor and linguistic nature.


CONCLUSIONS
The fact that other variations of SLI are not linked to the FOXP2 gene raises the need for further research into the genetic bases of the disorder, while also suggesting that it would be advisable to reassess the phenotypic scope of the variant associated to the mutation of this gene.
Benítez-Burraco
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A
Departamento de Lengua Española, Lingüística y Teoría de la Literatura, Facultad de Filología, Universidad de Sevilla, Palos de la Frontera, s/n, E-41004 Seville, Spain. abenitez@us.es
D000595:Amino Acid Sequence; D001921:Brain / Q000002:abnormalities / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D003001:Cloning, Molecular; D004200:Diseases in Twins; D047108:Embryonic Development / Q000235:genetics; D005260:Female; D051858:Forkhead Transcription Factors; D005786:Gene Expression Regulation; D018740:Genetic Heterogeneity; D006801:Humans; D007805:Language Development Disorders / Q000145:classification / Q000235:genetics*; D008297:Male; D008969:Molecular Sequence Data; D009154:Mutation; D009419:Nerve Tissue Proteins / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D009474:Neurons / Q000378:metabolism; D009928:Organ Specificity; D010375:Pedigree; D010641:Phenotype; D011401:Promoter Regions, Genetic; D020033:Protein Isoforms / Q000096:biosynthesis / Q000502:physiology; D014157:Transcription Factors / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D014158:Transcription, Genetic
C465448:FOXP2 protein, human; D051858:Forkhead Transcription Factors; D009419:Nerve Tissue Proteins; D020033:Protein Isoforms; D014157:Transcription Factors