TAPT1 encodes a highly conserved protein that localizes to the centrosome and/or ciliary basal body. Mutations in TAPT1 disrupt Golgi morphology and trafficking and normal primary cilium formation and these mutations are congenitally manifested by severe undermineralization of the intra-uterine skeleton. A mutation in the mouse ortholog of TAPT1 results in homeotic, posterior-to-anterior transformations of the axial skeleton which are similar to the phenotype of mouse homeobox C8 gene mutants. In mouse, TAPT1 is thought to function downstream of homeobox C8 to transduce extracellular patterning information during axial skeleton development.