The gene that encodes REP1 was first identified as a critical gene in choroideremia, an X-linked recessive disease of the retina that results in progressive degeneration of the retina, the RPE, and the choroid.29 Choroideremia results from defects in the gene that encodes REP1 in humans (CHM), mice (Chm), and zebrafish (chm).19, 30, 31, 32 In addition to the eye defect, chm−/− mutant zebrafish show embryonic lethality at 5 d.p.f. with cell death throughout the body20 and, we also discovered that evark10mutant zebrafish show aberrant development with cell death (Supplementary Figure S1). This evidence concerns the gene CHM and choroideremia.