Transcription factors in disease

Mutations affecting several predominantly tissue-specific transcriptional regulators have recently been associated with disease phenotypes. Although the mutational spectrum is variable, many of the reported cases involve clear loss-of-function mutations - such as Waardenburg syndrome type 1, aniridia and Rubinstein-Taybi syndrome - suggesting that the genetic mechanism involved in disease is haplo-insufficiency. The high degree of dosage sensitivity often appears to affect only a subset of the tissues that express the gene. Position effects with cytogenetic rearrangements well outside the coding region have been implicated for four of the genes discussed: POU3F4, SOX9, PAX6, and GLI3.