Although piebaldism has never been reported in humans with OS, all (100%) of the Naa10-/Y and Naa10tm1a/Y mice exhibited hypopigmentation on their belly (Figure 2B, upper), with this piebaldism quite varied in its extent but not appearing to correlate in any way with other phenotypes, such as hydrocephaly. This evidence concerns the gene NAA10 and Hydrocephalus.