Whereas the significant nuclear localization of wild-type MSX1 was detected, that of p.R151fsX20 MSX1 was not observed in the gene-transfected cells in a manner similar to p.W139X MSX1 (Fig 4A), which we recently reported to be a novel tooth agenesis causative mutant of MSX1 with a stop codon before the homeodomain [20]. The gene discussed is MSX1; the disease is tooth agenesis.