The group of retinal and vitreoretinal diseases (cone dystrophies, exudative vitreoretinopathies, macular degenerations, night blindness, retinitis pigmentosa) is particularly heterogeneous. Mutations in more than 300 genes can give rise to about 20 different retinal and vitreoretinal phenotypes. For more details please refer to:
Berger W, Kloeckener-Gruissem B, Neidhardt J (2010)
The molecular basis of human retinal and vitreoretinal diseases.
Prog Retin Eye Res 29:335-375
Disease classification according to phenotype
Figure: Classification of monogenic familial retinal and vitreoretinal diseases. Depending on the photoreceptor cell type that is affected, we discriminate rod and cone dominated diseases. As the names imply, one of the two photoreceptor cell types is affected predominantly. A third group are generalized photoreceptor diseases which involve both cell types, rods and cones. Another group, the vitreoretinopathies, also involves the vitreous in addition to the retina.