In 2001, the team identified in CS that the mutation is in the middle of a protein-coding gene. Using a combination of bioinformatics and RNA analyses, they discovered that the gene codes for a novel protein belonging to the forkhead-box (FOX) group of transcription factors. As such, it was assigned with the official name of FOXP2. When the researchers sequenced the "FOXP2" gene in the KE family, they found a heterozygous point mutation shared by all the affected individuals, but not in unaffected members of the family and other people. This mutation is due to an amino-acid substitution that inhibits the DNA-binding domain of the "FOXP2" protein. Further screening of the gene identified multiple additional cases of "FOXP2" disruption, including different point mutations and chromosomal rearrangements, providing evidence that damage to one copy of this gene is sufficient to derail speech and language development.