These data demonstrate that Rodriguez syndrome is a dominant disorder that is allelic with Nager syndrome, and show that the two disorders belong to a spectrum unified by mutations in SF3B4. SF3B4 mutations have also been found in an independent set of Rodriguez syndrome cases (New dominant mutations in SF3B4 encoding an mRNA spliceosomal protein important in embryonic limb patterning underlie Rodriguez acrofacial dysostosis. This evidence concerns the gene SF3B4 and Nager syndrome.