Genetics of childhood disorders: XXXVII. News flash: a gene for expressive language.

The ability to speak is uniquely human. Although other species are capable of communicating with each other, the use of speech is a distinguishing feature of Homo sapiens. Is it possible that this trait is determined by specific genes? This question has been debated by linguists for many decades, and both sides of the argument have vocal supporters. The recent isolation of a gene that appears to be critical for the normal acquisition of language is a remarkable achievement and important to clinicians and researchers alike. The researchers’ overall strategy is instructive because a similar strategy is likely to prove successful with other childhood psychiatric disorders including autism and Tourette syndrome. Each of the component steps in this process have been reviewed in prior columns: identifying an extended family for study, using linkage or karyotyping techniques to pinpoint the chromosomal location of the gene, pulling out the mutated gene, and determining the normal function of the encoded protein. Approximately 5% of children are significantly impaired in acquiring expressive and/or receptive language despite the absence of any detectable deficits in hearing, intelligence, or socioeconomic status. Twin studies have established that genetic factors play a significant role in certain developmental language disorders such as expressive language disorder without articulation difficulties, which is the most frequent expressive lanGenetics of Childhood Disorders: XXXVII. News Flash: A Gene for Expressive Language