MSX1 and tooth agenesis: Several other missense and nonsense mutations have also been reported in tooth agenesis patients.14,15 Homozygous deletion of Msx1 in mice results in an arrest of tooth and nail development; this also supports the important function of the MSX1 protein in tooth development.5 Compared to other findings, the mutation in the 3’-UTR region in this study may explain the importance of post-transcriptional regulation or mRNA stability of MSX1. The exact functional consequences of this particular mutation should be investigated in further studies.