RESUMO
SOX10 protein is a key transcription factor during neural crest development. Mutations in SOX10 are associated with several neurocristopathies such as Waardenburg syndrome type IV (WS4), a congenital disorder characterized by the association of hearing loss, pigmentary abnormalities, and absence of ganglion cells in the myenteric and submucosal plexus of the gastrointestinal tract, also known as aganglionic megacolon or Hirschsprung disease (HSCR). Several mutations at this locus are known to cause a high percentage of WS4 cases, but no SOX10 mutations had been ever reported associated to isolated HSCR patient. Therefore, nonsyndromic HSCR was initially thought not to be associated to mutations at this particular locus. In the present study, we describe the evaluation of the SOX10 gene in a series of 196 isolated HSCR cases, the largest patient series evaluated so far, and report a truncating c.153-155del mutation. This is the first time that a SOX10 mutation is detected in an isolated HSCR patient, which completely changes the scenario for the implications of SOX10 mutations in human disease, giving us a new tool for genetic counseling.