The spatiotemporally dynamic expression of polr1a, polr1c, and polr1d during zebrafish embryogenesis, particularly in craniofacial tissues, is consistent with their loss-of function phenotypes as well as with the etiology and pathogenesis of Acrofacial dysostosis, Cincinnati type and TCS, respectively. The gene discussed is POLR1D; the disease is acrofacial dysostosis.