Retinal dystrophies are predominantly caused by mutations affecting the visual phototransduction system and cilia, with few
genes identified that function to maintain photoreceptor survival. We reasoned that growth factors involved with early embryonic
retinal development would represent excellent candidates for such diseases. Here we show that mutations in the transforming
growth factor-β (TGF-β) ligand Growth Differentiation Factor 6, which specifies the dorso-ventral retinal axis, contribute to Leber congenital amaurosis. Furthermore, deficiency of gdf6 results in photoreceptor degeneration, so demonstrating a connection between Gdf6 signaling and photoreceptor survival. In
addition, in both murine and zebrafish mutant models, we observe retinal apoptosis, a characteristic feature of human retinal
dystrophies. Treatment of gdf6-deficient zebrafish embryos with a novel aminopropyl carbazole, P7C3, rescued the retinal apoptosis without evidence of toxicity.
These findings implicate for the first time perturbed TGF-β signaling in the genesis of retinal dystrophies, support the study
of related morphogenetic genes for comparable roles in retinal disease and may offer additional therapeutic opportunities
for genetically heterogeneous disorders presently only treatable with gene therapy.