This premise is supported by the labeling of choroidal but not RPE cells using a Pax3-green fluorescent protein reporter in mice [67], by the identification of Pax3 but not Pax6 in the transcriptional signature of murine choroidal melanocytes [68,69], and by reports that PAX3 mutations in patients with Waardenburg syndrome cause choroidal hypopigmentation without affecting RPE pigmentation [70,71,72]. The gene discussed is PAX3; the disease is Waardenburg syndrome.