While these results could indicate defects in PUFA supply from the RPE to the retina, such a significant loss of DHA (>7-fold compared to WT) at least partially reflects the progression of retinal degeneration in the rd6 mice, which lack about one-third of their DHA-rich photoreceptors at 1 mo of age (SI Appendix, Fig. S2). This evidence concerns the gene MFRP and retinal degeneration.