Furthermore, hRPCs responded to the diseased AMD cybrids with elevated expression levels of putative neuroprotective factors: MDK (fold change = 3.53, p < 0.01, Figure 5(c)), PTN (fold change = 2.71, p < 0.01, Figure 5(d)), and FGF2 (fold change = 2.16, p < 0.01, Figure 5(e)). This evidence concerns the gene PTN and age-related macular degeneration.