TFII-I gene family during tooth development: candidate genes for tooth anomalies in Williams syndrome

Williams syndrome is a rare congenital disorder involving the cardiovascular system, mental retardation, distinctive facial features, and tooth anomalies. It is caused by the heterozygous deletion of approximately 1.6 Mb encompassing 28 genes on human chromosome 7q11.23. It has been suggested that the genes responsible for craniofacial anomalies are located in the telomeric end region, which harbors three members of the TFII-I gene family (Tassabehji et al. [2005] Science 310:1184). To recognize potential candidate genes for the tooth anomalies in Williams syndrome, we carried out comparative in situ hybridization analysis of members of TFII-I gene family during murine odontogenesis. Gtf2i showed widespread expression in the developing head but was higher in the developing teeth than surrounding tissues throughout tooth development. At the bud stage, Gtf2ird1 and Gtf2ird2 were expressed in the epithelial buds. At the early bell stage, expression of Gtf2ird1 and Gtf2ird2 was observed in preameloblasts and preodontoblasts.