Figure 2.

A, Amino acid sequence of main isoform of human FOXP2, showing all coding changes found thus far in individuals with developmental verbal dyspraxia (Lai et al. 2001; present study). Each change was absent from large numbers of control chromosomes, but only the R328X and R553H mutations are found in multiple affected members in families segregating developmental speech and language disorder. B, Nucleotide sequence of normal and expanded polyglutamine-encoding region identified in one of the probands in this study.